LIBRARY 


UNIVERSITY  OF  CALIFORNIA. 
"I 


Class 


PRACTICAL  TESTING  OF 
GAS  AND  GAS  METERS 


BY 

C.  H.  STONE,  B.S.,  M.S. 

CHIEF     INSPECTOR     OF    GAS 

PUBLIC    SERVICE    COMMISSION,    SECOND    DISTRICT,    NEW   YORK 
MEMBER    AMERICAN    CHEMICAL    SOCIETY 


FIRST  EDITION 

FIRST    THOUSAND 


NEW   YORK 

JOHN    WILEY   &   SONS 

LONDON:   CHAPMAN   &   HALL,  LIMITED 
1909 


T 


Copyright,  1909, 

BY 
C.  H.  STONE 


Stanbope  jprcss 

V.   H.   GILSON     C01IPAHT 
BOSTON.     U.S.A. 


PREFACE. 


THE  author  has  received  a  large  number  of  requests,  at 
different  times  and  from  various  men  connected  with  the  gas 
industry,  for  information  regarding  the  methods,  apparatus  and 
chemicals  used  in  the  testing  of  gas.  The  first  thought  was, 
naturally,  to  refer  the  inquirer  to  some  standard  work  where  he 
would  find  answers  to  all  of  his  questions.  Careful  investiga- 
tion, however,  failed  to  reveal  such  a  work.  The  nearest 
approach  was  Abady's  Gas  Analyst's  Manual;  but  this  was 
written  several  years  ago,  and  deals  with  the  subject  from  the 
English  standpoint.  There  are  very  many  points  of  difference 
between  the  procedure  on  this  side  of  the  water  and  that  abroad, 
and,  so  far  as  the  writer  knows,  no  book,  written  by  an  American 
and  dealing  purely  with  American  methods  of  gas  manufac- 
ture and  testing  and  thoroughly  up  to  date,  is  available  to-day. 
It  is  hoped  that  this  volume  may  fulfill  these  requirements. 

No  attempt  has  been  made  to  write  a  treatise  on  the  manu- 
facture and  distribution  of  gas;  these  topics  have  been  widely 
and  ably  covered  by  such  experts  as  King,  Newbigging,  Butter- 
field,  Latta,  and  many  others.  Only  where  the  methods  of  man- 
ufacture were  intimately  connected  with  the  interpretation  of 
chemical  or  other  tests  have  the  former  been  touched  upon. 
The  writer's  chief  aim  has  been  to  explain  clearly,  simply  and 
fully  such  tests  as  would  be  of  practical  service  to  the  gas  man- 
ager, chemist  or  photometrist,  and  to  make  such  comments  and 
suggestions  as  might  guide  him  in  his  choice  of  apparatus  or 
process  and  assist  him  to  secure  accurate  and  useful  results  there- 
with. For  this  reason  all  chemical  processes,  reactions  and  cal- 
culations have  been  explained  at  a  length  which  may  seem 
wearisome  to  the  expert  chemist.  It  is  hoped,  however,  that 


192872 


iv  PREFACE 

even  he  will  find  in  this  book  a  compilation  of  processes  and 
forms  of  apparatus  which  may  save  much  tiresome  searching  of 
journals  and  text-books.  Many  of  the  later  forms  of  calori- 
meters, for  example,  have  been  described  in  different  technical 
journals  during  1908,  and*  a  brief  account  of  these,  together  with 
the  original  reference,  is  given  in  the  chapter  on  calorimetry. 

To  the  state  or  municipal  inspector  we  trust  that  the  work  will 
appeal  by  giving  him  a  broader  view  of  what  is  being  done  in  the 
field  of  inspection  in  other  states.  As  the  writer  knows  from  his 
own  experience,  too  often  is  an  inspector  so  tied  down  by  restric- 
tions, so  hampered  by  routine  work,  and  so  near-sighted  by  reason 
of  the  limited  field  of  his  vision,  that  he  not  only  makes  no  per- 
sonal progress  toward  broad-mindedness,  but  becomes  an  actual 
drag  on  the  wheels  of  progress. 

To  the  student,  whether  in  the  college  or  commencing  work 
for  a  gas  company,  it  is  trusted  that  this  book  may  prove  a  help 
by  leading  him  by  easy  journeys  over  the  rather  troublesome 
roads  of  photometry,  calorimetry  and  the  chemical  analysis  of 
gas. 

Finally,  at  the  risk  of  repetition,  let  it  be  said  that  the  chief 
aim  of  the  writer  has  been  to  put  before  managers  and  others 
who  have  had  no  chemical  training  and  to  whom  the  words 
"calorimetry"  and  "photometry"  mean  nought  save  routine 
tests  but  little  understood;  whose  principal  ambition  is  to  manage 
their  plants  economically,  and  at  the  same  time  satisfactorily  in 
other  ways;  the  aim,  I  say,  is  to  put  before  these  men  the  sub- 
jects connected  with  gas  testing  so  plainly  that  what  has  hereto- 
fore been  but  dry  bones  to  them  may  become  a  living  reality, 
which  shall  aid  them  in  their  present  positions  and  at  the  same 
time  open  up  greater  possibilities  for  the  future. 

It  seems  necessary  for  the  writer  to  state  that  he  alone  is 
responsible  for  the  opinions  expressed  in  this  volume,  and  that 
they  are  not  in  any  sense  to  be  taken  as  an  index  of  the  ideas  or 
policy  of  the  Public  Service  Commission,  by  which  he  is  employed. 
Neither  is  it  to  be  necessarily  assumed  that  the  writer  will  recom- 
mend his  beliefs  for  the  Commission  to  put  into  practice,  since 


PREFACE  V 

many  things  are  both  possible  and  desirable  in  the  scientific  and 
business  world  which  could  not,  at  least  in  the  present  age,  be 
carried  out  by  governmental  bodies. 

The  author  is  indebted  to  D.  McDonald  &  Company  for  the 
excellent  cut  of  the  standard  cubic  foot,  and  to  the  American 
Meter  Company  for  their  kind  loan  of  cuts  of  the  Siphon  Pres- 
sure Gauge,  the  Arch  Gauge,  and  meter  prover. 


TABLE   OF    CONTENTS. 


PART   I.    PHOTOMETRY. 

CHAPTER  PAGE 

I.   THE  PHOTOMETER  AND  ACCESSORIES 3 

II.   STANDARDS  AND  BURNERS 24 

III.  CANDLEPOWER  TESTS  OF  COAL  AND  WATER  GAS,  USING  CANDLES 

AS  STANDARDS 43 

IV.  PHOTOMETRIC  WORK  WITH  OTHER  STANDARDS  AND  GASES 61 

V.   INTERPRETATION  OF  RESULTS  AND  LEGAL  REQUIREMENTS 70 

PART  II.     CHEMICAL  TESTS. 

I.   CARBONIC  ACID  AND  SULPHURETTED  HYDROGEN 85 

II.   TOTAL  SULPHUR 106 

III.  OTHER  IMPURITIES 143 

IV.  THE  ANALYSIS  OF  GAS .f 164 

PART  HI.     CALORIMETRY,   SPECIFIC   GRAVITY   AND  PRESSURE. 

I.   THE  JUNKER  AND  BOYS  CALORIMETERS 197 

II.   OTHER  INSTRUMENTS  AND  METHODS 219 

III..  CONSIDERATION  OF  RESULTS 244 

IV.  SPECIFIC  GRAVITY  AND  PRESSURE 250 

PART  IV.    TESTING  OF  METERS. 

I.   THE  CUBIC  FOOT  AND  METER  PROVER 269 

II.  THE  METHOD  OF  TESTING  METERS 287 

APPENDIX 301 


TABLE    OF    ILLUSTRATIONS. 


PIG.  PAGE 

1.  Closed  Bar  Photometer , 7 

2.  Suggs-Letheby  Photometer 9 

3.  Standard  Bar  Photometer  (Style  B) 10 

4.  Portable  Photometer 15 


ERRATA. 

p.  86.     Symbol  H2O2  should  be  H,O. 

p.  89,  line  17.     Afterword  "flask"  add  "add  barium  chloride  in 
excess  and  filter." 

p.  146,  line  14.     Afterwords  "  2.14  grains  hydrochloric  acid"  add 
"  per  liter." 

p.  273,  line  20.     After  word  "  inches  "  insert  "  barometric." 


26.  Elliott's  Analysis  Outfit  (Old  Style) $ 180 

27.  Elliott's  Analysis  Outfit  (New  Style) 181 

28.  Orsat- Lunge  Apparatus .' 181 

29.  Hinman's  Analysis  Apparatus ^3 

30.  Junker  Calorimeter J99 

31.  Junker  Calorimeter  Modified 211 

32.  Boys  Calorimeter 212 

33.  Simmance-Abady  Calorimeter 220 

34.  Simmance-Abady  Calorimeter 222 

35.  Sargent  Calorimeter 227 

36.  Sargent  Calorimeter 229 

ix 


TABLE    OF    ILLUSTRATIONS. 


FIG.  PAGE 

1.  Closed  Bar  Photometer 7 

2.  Suggs-Letheby  Photometer 9 

3.  Standard  Bar  Photometer  (Style  B) 10 

4.  Portable  Photometer 15 

5.  Carcel  Lamp 28 

6.  Hefner  Lamp 29 

7.  Elliott  Lamp. 32 

8.  Edgerton  Sleeve 34 

9.  Pentane  Lamp 38 

10.  Metropolitan  No.  2  Burner 40 

11.  Method  of  Cutting  Candles 52 

12.  Expansion  of  Gas 57 

13.  Acetylene  Burner. 69 

14.  Rudorff's  Apparatus  for  Carbonic  Acid 93 

15.  Recording  Apparatus  for  Carbonic  Acid 95 

16.  Harcourt's  Color  Test m 

17.  Referees'  Sulphur  and  Ammonia  Apparatus 118 

18.  Aerorthometer 122 

19.  Hinman- Jenkins  Sulphur  Apparatus 127 

20.  Ammonia  Bulb  and  Glass  Flower 146 

21.  Lacey's  Apparatus  for  Ammonia 152 

22.  Coleman  and  Smith's  Naphthalene  Apparatus 160 

23.  Sample  Tube 165 

24.  Hempel's  Gas  Analysis  Apparatus 176 

24A  Hempel's  Pipettes 177 

246  Hempel's  Correction  Tube 178 

25.  Taplay's  Modification  of  Hempel 179 

26.  Elliott's  Analysis  Outfit  (Old  Style) ^ 180 

27.  Elliott's  Analysis  Outfit  (New  Style) 181 

28.  Orsat- Lunge  Apparatus .' 181 

29.  Hinman's  Analysis  Apparatus 183 

30.  Junker  Calorimeter 199 

31.  Junker  Calorimeter  Modified 211 

32.  Boys  Calorimeter 212 

33.  Simmance-Abady  Calorimeter 220 

34.  Simmance-Abady  Calorimeter 222 

35.  Sargent  Calorimeter 227 

36.  Sargent  Calorimeter 229 

ix 


X  TABLE   OF   ILLUSTRATIONS 

FIG.  PAGE 

37.  Simmance-Abady  Portable  Calorimeter 236 

38.  Fery  Calorimeter 240 

39.  Graefe  Calorimeter 242 

40.  Bristol  Pressure  Gauge 254 

41.  Bristol  Pressure  Gauge , .  .  255 

42.  Siphon  or  U  Gauge 256 

43.  Arch  Pressure  Gauge 257 

44.  Lux  Balance 259 

45.  Schilling's  Specific  Gravity  Apparatus 260 

46.  Jenkins'  Specific  Gravity  Apparatus 262 

47.  Referees'  Cubic  Foot  Bottle 271 

48.  American  Standard  Cubic  Foot 272 

49.  Meter  Prover 275 

50.  Meter  Prover 278 

51.  Meter  Prover  and  Meter  Connected  for  Test 289 


PART    I. 


PHOTOMETRY. 


OF  THE 

UNIVERSITY 

OF 


PRACTICAL   TESTING   OF   GAS 
AND   GAS   METERS 


PART  I. 
PHOTOMETRY. 


CHAPTER  I. 
PHOTOMETER  AND  ACCESSORIES. 

THE  selection  of  a  suitable  location  for  the  photometer  room 
and  the  proper  construction  and  equipment  of  the  latter  are 
matters  of  primary  and  vital  importance.  It  is  the  custom  with 
a  large  number  of  gas  companies  to  locate  the  photometer  at  the 
works  in  order  that  constant  watch  may  be  kept  over  the  output 
of  the  plant.  The  works  foreman,  or  some  competent  man,  is 
detailed  to  take  the  candlepower  at  stated  intervals,  or,  in  specific 
cases,  at  certain  points  in  each  run;  and  from  his  results  the 
superintendent  is  able  to  determine  whether  the  heats  have  been 
right,  whether  the  run  has  been  too  long  or  short,  and  in  general 
whether  the  make  has  been  conducted  to  the  best  advantage. 
Moreover,  the  gasmaker  himself  is  thus  informed  of  the  quality 
of  the  product,  and  consequently  works  with  more  intelligence  and 
certainty. 

There  are  reasons,  however,  which  in  certain  cases  would  point 
to  some  location  for  the  photometer  room  other  than  at  the  works. 
In  the  first  place  it  is  not  always  well  to  have  the  candlepower 
taken  by  a  man  who  is  directly  interested  in  the  result,  as  is  the 
case  with  nearly  all  men  at  the  works.  However  honest  the 

3 


4  GAS  AND   GAS   METERS 

employee  may  be,  if  he  has  formed  an  opinion  that  the  gas  is  of  a 
certain  quality,  he  is  liable  to  allow  his  judgment  to  influence  the 
test,  and  only  those  who  are  familiar  with  such  work  know  how 
easy  it  is  to  move  the  sight  box  a  fraction  of  an  inch  one  way  or 
the  other  and  believe  that  it  makes  no  practical  difference  with 
the  results. 

Moreover,  the  candlepower  determination  involves  certain 
refinements  in  execution  and  calculation  which  are  more  in  the 
province  of  an  educated  man,  and  many  companies  prefer  for  this 
reason  to  intrust  the  test  to  some  member  of  their  office  force. 

Again,  the  gas  at  the  works  is  not  of  the  same  quality  as  that 
delivered  to  the  consumer.  This  is  especially  true  in  the  winter 
time,  when  it  is  not  uncommon  to  find  a  loss  of  from  one  to  three 
candlepower  between  the  works  and  a  point  at  a  distance  of  a  mile 
therefrom.  This  is  of  peculiar  significance  in  states  and  cities 
where  the  company  is  under  some  form  of  governmental  super- 
vision, for  in  all  such  cases  the  test  of  the  inspector  will  be  made 
at  a  distance  varying  from  one-quarter  of  a  mile  to  one  and  one-half 
miles  from  the  works  of  the  company.  The  one-mile  limit  so 
frequently  set  has  its  origin  in  the  fact  that  experiments  have 
shown  that  as  a  rule  after  the  gas  has  traveled  one  mile  in  the  mains 
the  loss  in  candlepower  has  practically  attained  a  maximum. 

It  has  been  suggested  that  allowance  be  made  for  this  by  assum- 
ing a  definite  loss  of  candlepower  and  then  making  the  gas  at  the 
works  sufficiently  rich  to  compensate  for  such  loss.  The  objections 
to  such  procedure  are  twofold.  First,  it  is  impossible  to  assume 
any  definite  loss,  since  the  latter  depends  not  only  on  the  tempera- 
ture in  the  mains,  but  also  on  other  factors  connected  with  the 
composition  of  the  gas  which  it  is  not  feasible  to  accurately  regulate; 
and  second,  that  a  sudden  rise  in  external  temperature  might  leave 
the  gas  so  rich  as  to  be  a  menace  to  Welsbach  mantles  and  to 
ceilings. 

A  more  satisfactory  way  to  overcome  these  difficulties  would 
seem  to  be  to  locate  the  photometer  at  the  office  of  the  company, 
when  such  office  is  over  a  quarter  of  a  mile  from  the  works;  to 
instruct  some  one  of  the  office  force  in  the  science  of  photometry, 


PHOTOMETER  AND    ACCESSORIES  5 

and  then  from  time  to  time  notify  the  works  by  telephone  of  the 
quality  of  gas  which  is  being  delivered  at  the  office. 

Having  determined  upon  the  site  for  the  photometer  room,  the 
next  step  is  to  see  that  the  latter  is  properly  constructed  and 
equipped.  As  in  most  cases  it  is  impracticable  to  build  a  room 
especially  for  photometric  work,  the  problem  becomes  one  of 
alterations  in  existing  conditions;  and  to  understand  what  these 
should  be,  it  is  only  necessary  to  enumerate  the  qualifications 
desirable  in  such  a  room. 

The  ventilation  may  be  said  to  be  the  first  and  most  important 
feature,  since  neither  gas,  candles  nor  standard  lamp  will  burn 
properly  or  at  their  maximum  efficiency  without  an  abundant 
supply  of  pure  air.  To  this  end  a  room  should  be  selected  which 
is  not  less  than  15  feet  long,  9  feet  wide,  and  12  feet  high.  The 
best  ventilation  is  secured  by  an  opening  near  the  floor  for  the 
admission  of  the  fresh  air,  and  one  in  or  near  the  ceiling  for  the 
exit  of  the  impure  air.  The  inlets  should  have  a  total  area  of 
10  square  feet  for  a  room  of  the  size  above  mentioned;  they  should 
extend  around  the  entire  room,  and  should  be  so  constructed  as  to 
allow  of  a  free  inrush  of  air  without  occasioning  drafts.  The 
importance  of  proper  ventilation  cannot  be  overestimated;  those 
who  have  had  experience  with  the  use  of  candles  in  a  close  and 
impure  atmosphere  will  appreciate  this  fact,  for  the  effect  on  the 
candles  is  visible  to  the  naked  eye.  With  other  standards  and 
with  gas  flames  the  result  is  similar,  though  less  marked,  and  in 
the  appendix  will  be  found  formulae  for  correcting  for  the  amount 
of  moisture,  carbonic  acid,  etc.,  in  the  atmosphere.  These  correc- 
tions are,  of  course,  not  absolute,  and  it  must  not  be  assumed  that, 
by  the  use  of  them,  the  necessity  of  proper  ventilation  is  obviated. 

It  is  well,  whenever  possible,  to  select  a  room  which  has  no 
wall  exposed  to  the  outside  air,  or  to  conditions  which  will  make 
its  temperature  different  from  that  of  the  other  walls,  since  such 
conditions  give  rise  to  drafts.  Some  arrangement  should  be 
made  whereby  the  temperature  of  the  room  may  be  kept  con- 
stant at,  say,  70  degrees,  throughout  the  entire  year.  This  is  of 
vital  importance  for  two  reasons.  In  the  first  place,  it  has  been 


6  GAS   AND    GAS   METERS 

shown  by  Jenkins  and  others  that  the  candlepower  of  a  gas 
increases  with  increase  of  temperature,  and  a  table  illustrating 
this  fact  will  be  found  in  the  appendix.  This  will  seem  per- 
fectly natural  if  we  remember  the  effect  produced  in  a  burner  by 
preheating  the  air  supply  thereof.  The  second  reason  is  still 
more  important,  but  somewhat  less  easy  of  comprehension. 
The  illuminating  value  of  gas  is  largely  derived  from  certain 
hydrocarbon  vapors  which  are  more  or  less  condensible.  If  a 
gas  carrying  such  vapors  passes  through  a  cold  pipe,  condensa- 
tion takes  place,  and  the  hydrocarbons  are  deposited  in  the  pipe 
and  thus  lost  to  the  gas.  If  now  the  temperature  of  this  same  pipe 
should  suddenly  rise,  the  condensed  vapors  will  be  picked  up  by 
the  gas  in  passing,  and  thus  cause  a  temporary  increase  in  candle- 
power.  These  statements  apply  with  equal  truth  to  the  photom- 
eter meter,  because  the  ability  of  the  water  in  that  meter  to 
absorb  vapors  decreases  with  increase  of  temperature.  Thus  it 
is  apparent  that  an  even  temperature  is  a  necessity  for  accurate 
work,  and  this  can  be  secured  if  the  photometer  room  is  built 
entirely  within  a  second  and  larger  room  which  is  itself  heated 
by  hot  air  and  kept  at  as  uniform  a  temperature  as  possible.  It 
is  perhaps  needless  to  say  that  no  heating  apparatus  of  any  kind 
should  be  placed  near  the  photometer. 

It  has  been  the  general  custom,  where  an  open-bar  photometer 
was  to  be  used,  to  paint  the  room  black.  Recent  experiments  by 
the  National  Bureau  of  Standards  show  that  such  procedure  is 
not  essential;  but  it  will  doubtless  make  the  photometric  work 
easier  to  the  average  operator  if  as  much  external  light  and 
reflection  as  possible  are  excluded  from  the  eye. 

Piping.  The  gas  to  be  tested  should  come  as  directly  as  pos- 
sible from  the  main  through  a  pipe  of  not  less  than  one-half  inch 
diameter,  and  should  not  be  allowed  to  pass  through  any  meter 
before  reaching  the  photometer.  It  is  well  to  cover  the  pipe 
with  some  non-conducting  material,  such  as  magnesia  pipe  cov- 
ering, in  order  to  prevent  changes  of  temperature  therein. 

If  the  gas  is  not  to  be  burned  continuously,  it  will  be  found 
advantageous  to  provide  a  blow-off  whereby  the  gas  which  has 


PHOTOMETER   AND   ACCESSORIES 


been  standing  in  the  pipe  may 
be  quickly  exhausted.  This  may 
be  accomplished  by  tapping 
the  pipe  just  before  the  pho- 
meter  meter,  inserting  a  T 
and  running  a  pipe  therefrom 
through  the  outer  wall  of  the 
building,  proper  precautions 
being  taken  to  see  that  the 
gas  escaping  from  this  blow- 
off  causes  no  injury  or  incon- 
venience to  anyone.  By  this 
t  simple  expedient,  gas  fresh 
«  from  the  main  can  be  obtained 
£  in  five  minutes,  while  to  secure 

o 

£  the  same  result  by  burning  the 
J  gas  in  the  photometer  might 
1  take  half  an  hour. 
Q  Stationary  Photometers.  For 
^  practical  use  in  this  country 
&o  there  are  but  two  general  styles 
fe  of  stationary  photometer,  the 
open  and  the  closed  bar.  Each 
has  its  strong  points  and  its 
defects,  its  advocates  and  its 
enemies.  The  closed-bar  pho- 
tometer as  manufactured  by 
the  American  Meter  Company 
(Fig.  i)  consists  essentially  of 
a  rectangular  tube  or  gallery  5 
feet  10  inches  long,  13^  inches 
wide  by  12  inches  deep,  which 
at  either  end  is  bolted  to  a 
cabinet  2  feet  9^  inches  high, 
24  inches  wide  and  18  inches  deep.  The  front  of  the  gallery 
is  composed  of  overlapping,  interchangeable  panels,  thus  excluding 


8  GAS    AND    GAS    METERS 

all  light  from  the  interior,  and  at  the  same  time  permitting  the 
use  of  the  sight  box  in  different  parts  of  the  gallery.  In  one  of 
the  cabinets  is  placed  the  standard  and  in  the  other  the  gas  pillar 
and  burner.  Ventilation  is  secured  through  15  holes,  ij  inches 
in  diameter,  in  the  bottom  of  each  chamber,  and  the  products  of 
combustion  and  impure  air  are  conveyed  away  through  brass 
chimneys  6  inches  in  diameter  arid  4!  inches  high.  On  the  lower 
front  edge  of  the  gallery  is  placed  a  graduated  scale  so  constructed 
that  a  direct  reading  of  candlepower  is  possible.  The  sight  box 
runs  on  a  track  within  the  gallery,  and  to  the  front  of  it  is 
attached  a  wooden  shield  which  passes  behind  the  gallery  panels. 
The  interior  of  the  gallery  is  painted  a  dull  black  and  fitted 
with  shields  to  prevent  reflection.  The  whole  apparatus  stands 
on  a  table  in  the  center  of  which  is  placed  the  meter  and  to  the 
left  of  the  latter  the  governor  and  pressure  gauge. 

The  advantages  claimed  for  this  style  of  photometer  are  that  it  is 
somewhat  cheaper  than  the  open  bar;  that  it  does  not  require  an 
entirely  dark  room  for  its  use,  and  that  the  flames  of  the  gas  and 
standard  are  less  subject  to  drafts.  On  the  other  hand,  it  is  urged 
that  the  ventilation  is  not  as  satisfactory  as  with  the  open  bar,  that 
there  is  danger  of  incorrect  results  due  to  reflections  in  the  interior 
of  the  gallery,  and  that  there  is  liable  to  be  a  considerable  change 
in  temperature  within  the  chambers  after  long  continued  burning 
of  the  gas  or  standard. 

The  open-bar  photometer,  known  as  the  Suggs-Letheby,  differs 
from  the  above  in  that  neither  gas,  standard  nor  bar  is  inclosed. 
It  consists  in  its  essential  features  of  a  bar  (Fig.  2),  extending  from 
the  gas  to  the  standard,  on  which  the  sight  box  runs.  The  scale  on 
this  bar  is  graduated  in  a  manner  similar  to  the  one  on  the  closed 
bar,  and  screens  are  set  at  definite  intervals  to  protect  against  reflec- 
tions. From  the  fact  that  both  the  gas  and  the  standard  are  unin- 
closed,  and  burn  in  the  open  air,  it  will  be  seen  that  the  ventilation 
is  better  than  with  the  closed  bar,  and  the  distance  of  the  sight  box 
from  the  table  and  wall  prevents  in  large  measure  the  reflection, 
which  is  one  of  the  objectionable  features  of  the  latter  instrument. 
The  cost  of  the  Letheby  is  slightly  greater  than  that  of  the  closed- 


PHOTOMETER   AND   ACCESSORIES  9 

bar  photometer  of  similar  size,  and  the  former  requires  a  separate 
and  special  room  for  its  use;  but  if  the  purchaser  is  not  compelled  to 
consider  the  financial  side  of  the  question,  an  open-bar  photometer 
should  be  installed.  For  smaller  companies  which  cannot  easily 
secure  the  necessary  room,  however,  the  closed-bar  photometer  will 
be  found  to  give  excellent  satisfaction,  and  the  results  obtained 


Fig.   2.     Suggs-Letheby  Photometer. 

therefrom  will  be  more  than  sufficiently  accurate  for  all  practical 
purposes.  The  Improved  Letheby  photometer  may  be  secured  as 
a  6o-inch,  8o-inch,  or  loo-inch  bar,  but  the  6o-inch  form  is  recom- 
mended by  the  Committee  of  the  American  Gas  Institute  1  both 
because  "  being  shorter  it  requires  less  space,  and  because  the  two 
light  sources  usually  compared  in  plain  gas  photometry  are  at  such 
relative  distances  from  the  disc  as  to  give  it  the  best  theoretical 
illumination  for  easily  comparing  the  star  or  other  figure  on  the 
disc."  The  divisions  on  the  6o-inch  scale  are,  however,  necessa- 
rily smaller  than  those  of  the  8o-inch  or  loo-inch  bars,  and  conse- 
quently more  difficult  to  read  accurately.  Moreover,  a  slight  move- 
ment of  the  sight  box  on  the  6o-inch  bar  causes  the  pointer  to  cover 

1  Proceedings  of  American  Gas  Institute,  October,  1907. 


IO 


GAS   AND    GAS    METERS 


more  spaces  than  a  similar  movement  would  cause  with  the  longer 
bars,  and,  therefore,  a  small  error  of  reading  makes  less  difference 
with  the  latter  form.  With  closed-bar  photometers  the  author 
believes  that  the  So-inch  type  is  the  one  most  generally  used. 


Fig.  3.     Standard  Bar  Photometer,  Style  B. 

The  cost  of  a  photometer  is  always  a  matter  of  interest  to  a  pros- 
pective purchaser,  and  for  the  benefit  of  such  the  prices  offered  by 
the  American  Meter  Company  of  New  York  City  are  herewith 
given  as  samples: 

8o-in.  closed-bar  mahogany  photometer  complete $260.00  net 

6o-in.  open-bar  (style  B)  photometer  complete 275.00  net 

loo-in.  open-bar  (style  B)  photometer  complete 300.00  net 

6o-in.  Sugg-Letheby  photometer  complete 550.00  net 

loo-in.  Sugg-Letheby  photometer  complete 600.00  net 

A  word  as  to  the  table  photometer  in  use  in  London  may  not  be 
out  of  place  at  this  time.  One  objection  to  all  forms  of  bar  photo- 


PHOTOMETER   AND   ACCESSORIES  II 

meters  is  that  the  standard  is  used  at  varying  distances  from  the  disc, 
and  the  nearer  the  standard  is  to  the  latter,  the  greater  is  the 
light  area  of  its  flame  at  the  disc.  Now,  in  securing  a  value  for  the 
standard,  the  disc  was  in  a  certain  definite  position  which  is  almost 
certain  to  be  different  from  that  at  which  it  stands  when  the  candle- 
power  of  the  gas  is  measured.  This  objection  has  been  overcome 
with  the  Table  Photometer  by  adopting  fixed  positions  for  standard, 
disc  and  light  to  be  tested,  and  gaining  equality  of  illumination  by 
varying  the  rate  of  flow  of  the  gas.  This  method,  however,  was 
found  to  be  unsatisfactory,  because  it  could  not  be  applied  to  gases 
which  differed  widely  in  candlepower,  nor  to  both  Argand  and  flat- 
flame  burners;  so  the  Notification  of  the  Gas  Referees  for  1907 
recommends  moving  the  flame  under  test.  This  does  not  seem 
desirable,  because  one  of  the  first  principles  of  photometry  is  that 
all  flames  should  be  kept  as  quiet  as  possible.  The  Table  Photom- 
eter has  been  carefully  tested  in  this  country,  and  the  consensus 
of  opinion  seems  to  be  that,  in  its  present  form,  it  is  not  the  equal  of 
the  bar  photometer  in  accuracy  and  ease  of  manipulation. 

Portable  Photometer.  For  the  use  of  inspectors  who  are  obliged 
to  test  gas  in  places  where  there  is  no  stationary  photometer,  and 
for  the  convenience  of  gas  companies  operating  plants  in  more  than 
one  locality,  it  has  been  found  necessary  to  devise  some  form  of 
photometer  which  could  be  easily  transported  from  place  to  place 
and  which  should  be  sufficiently  accurate  for  practical  purposes. 
Such  instruments  are  now  in  use  in  New  York  and  Massachusetts, 
as  well  as  with  some  of  the  larger  gas  companies,  and  for  the  benefit 
of  others  who  may  feel  the  need  of  these,  a  somewhat  detailed 
description  of  the  one  in  use  by  the  Public  Service  Commission, 
Second  District,  of  New  York,  with  the  directions  for  its  use,  is  now 
given. 

The  photometer  in  question  was  constructed  by  the  American 
Meter  Company  of  New  York,  and  cost  complete  about  $275.00. 
It  consists  of  an  outside  box  or  trunk  in  which  is  packed  the  bar, 
the  meter,  tubing  and  all  accessories.  The  trunk  is  a  rectangular 
box  of  f-inch  birch,  44  inches  long  by  lof  inches  wide  by  i6J  inches 
deep  on  the  outside.  It  is  constructed  of  three-ply  material  to 


12  GAS   AND    GAS   METERS 

prevent  warping  and  is  surrounded  by  four  bands  of  wood  screwed 
to  the  sides  and  9^  inches  apart. 

The  corners  are  protected  by  steel  pieces  which  are  riveted,  and 
one  end  is  strengthened  inside  and  out  by  a  sheet  of  aluminum 
which  is  also  riveted  on.  This  end,  which  when  the  photometer 
is  set  up,  is  to  be  uppermost,  is  pierced  by  a  hole  4  inches  in  dia- 
meter, which  when  the  trunk  is  packed  for  shipment  is  closed  by  a 
hinged  door  opening  inwards  and  which  is  also  reenforced  by  an 
aluminum  plate. 

The  lid  is  held  in  place  by  four  trunk  locks,  two  on  either  side 
and  near  the  ends,  and  by  two  hasps  in  the  center.  On  the  outside 
of  the  lid,  and  6J  inches  from  one  end,  an  aluminum  plate  8J  inches 
by  6|  inches  is  set  in,  which  contains  four  keyhole-shaped  openings 
or  sockets;  these  engage  with  four  brass  projections  on  the  end  of 
the  bar  and  serve  to  support  the  latter  while  in  operation.  A 
similar  plate  is  set  into  the  bottom  of  the  trunk,  and  immediately 
behind  this  is  a  door  opening  inwards. 

In  the  interior  the  trunk  is  divided  into  two  compartments  by  a 
wooden  partition  i  inch  thick  which  is  held  in  place  by  angle  irons. 
The  smaller  of  these  divisions,  9!  inches  by  9  inches,  serves  as 
packing  space  for  the  meter,  and  is  therefore  well  cushioned  on 
sides  and  bottom  with  rubber,  while  a  large  rubber  pad  on  the 
inside  of  the  lid  rests  on  top  of  the  meter  and  holds  it  in  place. 
In  the  corners  around  the  meter,  or  coiled  on  top  thereof,  are 
packed  the  tubing  and  the  curtain  for  the  gas  end.  The  other  com- 
partment, occupying  the  remainder  of  the  interior,  contains  the 
bar,  which  fits  tightly  enough  to  need  no  further  protection.  This 
bar  is  of  f-inch  material,  is  6oJ  inches  by  8  inches  by  7  inches 
outside  dimensions,  and  is  hinged  at  the  center  so  that  one-half 
may  be  folded  over  on  the  other. 

When  extended  to  its  full  length  the  parts  are  held  together  by 
a  brass  pin  passing  through  a  narrow  but  heavy  strip  of  brass, 
which  projects  from  the  one-half,  and  then  into  a  metallic  socket 
in  the  other  half.  The  ends  of  the  bar  are  protected  by  aluminum 
plates  on  which  set  the  locks  which  engage  with  the  trunk  and 
cover.  The  edges  are  bound  with  aluminum,  and  plates  of  the 


PHOTOMETER   AND   ACCESSORIES  13 

same  metal  strengthen  the  portion  of  the  bar  around  the  center 
joint  and  surround  each  end  for  a  space  of  4  inches. 

Ten  inches  from  one  end  are  two  circular  holes  4  inches  in 
diameter,  one  in  the  bottom  and  the  other  directly  above  it  in  the 
top  of  the  bar;  these  serve  for  the  ventilation  of  the  candles  and 
supply  room  for  the  swing  of  the  balance.  On  the  side  of  the  bar 
between  these  openings  is  a  door  8  inches  by  4  inches  through 
which  the  balance  and  candles  are  reached  and  attended  to. 

Within  the  bar  are  packed  the  chimney,  balance,  trumpet  tube, 
sight  box,  and  burner  board.  The  chimney  is  contained  in  a 
light  metal  case,  from  one  end  of  which  projects  a  pin  and  from 
the  other  a  strip  of  metal  perforated  by  a  screw  hole.  The  pin 
engages  in  a  socket  at  the  end  of  the  bar  and  just  behind  the 
candle  balance,  while  the  strip  is  firmly  screwed  down  with  a  thumb 
nut. 

The  base  of  the  balance  is  permanently  fastened  in  place  in  the 
center  of  the  bar  and  just  beyond  the  circular  holes.  The  beam 
is  perforated  in  the  center  of  the  semicircle  formed  by  the  arms 
carrying  the  knife  edges,  and  through  this  opening  a  thumb  nut 
fastens  the  end  to  the  top  of  the  bar  while  the  tines  of  the  pointer 
pass,  one  on  either  side  of  a  stationary  pin.  The  balance  pan 
and  candle  holder  are  secured  in  position  above  the  chimney 
holder  by  a  thumb  nut  with  a  very  broad  surface  which  passes 
through  a  hole  in  the  pan  and  into  a  socket  in  the  woodwork. 

The  burner  board  is  fastened  by  thumb  nuts  to  the  bottom  of 
the  bar  underneath  the  beam  of  the  balance.  The  top  of  the 
sight  box  is  formed  of  a  long  plate  of  tin  which  projects  some  six 
inches  beyond  the  working  parts  of  the  box.  Through  each  of 
these  projections  a  hole  is  bored  three-quarters  of  an  inch  in  dia- 
meter, and  nuts  with  very  broad  bearing  surfaces  pass  through 
these  and  fasten  the  sight  box  to  the  top  of  the  bar.  The  trumpet 
tube  is  pierced  by  a  small  hole  near  the  rim,  and  a  thumb  nut  holds 
this  in  place  near  the  center  of  the  bar.  The  interior  of  the  entire 
gallery  is  lined  with  black  velvet,  and  the  exterior,  the  trunk, 
meter,  burner  board,  balance  and  all  metallic  parts  are  painted  a 
dull,  non-reflecting  black. 


14  GAS   AND   GAS   METERS 

The  meter  is  a  dry  one  and  is  classed  as  a  two-light;  it  is  cylin- 
drical in  form  and  has  three  diaphragms.  The  inlet  and  outlet 
are  provided  with  valves  especially  adapted  for  making  connections 
with  rubber  tubing.  The  top  is  not  soldered  but  is  closed  by  a 
large  plate  which  is  screwed  on,  the  joint  being  made  tight  by  a 
rubber  gasket.  This  is  a  great  convenience,  as  it  is  often  necessary 
to  clean  the  valves  and  occasionally  to  adjust  the  meter.  The 
dial  is  4  inches  in  diameter  and  is  divided  into  thousandths  of  a 
foot.  The  inlet  and  outlet  tubes  are  within  the  case,  thus  obviating 
the  danger  of  damage  during  transit.  An  opening  in  the  top  of 
the  meter  5  inches  deep,  and  of  course  not  connecting  with  the 
interior,  permits  the  insertion  of  a  thermometer. 

The  balance  is  of  the  type  commonly  used  in  this  country  with 
stationary  photometers,  the  upright  being  omitted,  and  the  piece 
bearing  the  sockets  for  the  knife  edges  being  shortened  to  meet 
the  requirements  of  its  position. 

The  sight  box  is  of  the  customary  variety,  and  is  provided  with 
a  bevel  gear  for  rotating  the  disc.  The  trumpet  tube  has  a  broad 
base,  in  the  corners  of  which  are  four  holes  which  slip  over  nuts 
on  the  top  plate  of  the  sight  box;  the  tightening  of  these  nuts 
then  holds  the  tube  in  position. 

The  burner  board  is  a  piece  of  wood  8  inches  by  3  inches  on 
which  three  burners  may  be  screwed.  The  central  one  has  a 
broad  base  and  an  arm  for  connecting  with  the  gas  supply;  the 
others  are  merely  for  the  transportation  of  other  burners.  The 
entire  apparatus  weighs  125  pounds,  and  may  be  packed  or 
unpacked  and  set  up  in  three  minutes. 

In  preparing  the  photometer  for  use  the  lid  is  first  removed 
and  set  up,  with  aluminum  plate  out,  against  some  solid  object, 
as  a  desk  or  the  wall  of  a  room.  The  bar  is  then  lifted  from  the 
trunk,  which  is  set  on  end  at  a  distance  from  the  lid  about  equal 
to  the  total  length  of  the  bar.  The  balance,  chimney  and  other 
accessories  are  unscrewed  and  removed  from  the  interior.  The 
sight  box  is  placed  in  position  and  the  trumpet  tube  attached 
thereto;  the  halves  of  the  bar  are  now  swung  together  and 
clamped  in  place.  The  proper  end  is  then  fastened  to  the  plate 


PHOTOMETER   AND    ACCESSORIES  15 

on  the  lid  by  means  of  the  socket  joint  already  mentioned,  and 
the  other  end  is  similarly  secured  to  the  trunk.     (Fig.  4.) 

The  burner  board  is  next  set  up  within  the  trunk ;  the  constant 
position  of  this  is  secured  by  two  pins  on  either  side  of  the  inside 
walls,  which  engage  with  holes  in  two  small  brass  plates  pro- 
jecting on  either  side  of  the  burner  board.  These  pins  are 


Fig.  4.     Portable  Photometer. 


placed  at  such  a  point  that,  with  the  board  in  position  and  the 
burner  thereon,  the  center  of  the  flame  will  be  60  inches  from 
the  center  of  the  candle  flames. 

The  meter  is  now  placed  on  top  of  the  bar  and  connected  with 
the  gas  supply  and  to  the  burner  by  flexible  metallic  tubing, 
The  chimney  is  removed  from  its  case,  cleaned  and  placed  on 
the  burner.  The  doors  in  the  top  of  the  trunk  and  the  one  lead- 
ing to  the  bar  are  opened.  Then  light  the  gas  and  allow  it  to 
burn  while  finishing  the  preparation  of  the  rest  of  the  photom- 
eter. 

Insert  the  thermometer  in  the  meter,  and  if  an  aneroid  barom- 
eter is  used,  open  and  place  it  on  the  bar  near  the  meter.  The 
balance  is  next  to  be  set  up  within  the  photometer  and  adjusted, 
and  the  candles  lighted.  The  alignment  of  the  latter  is  accom- 
plished by  means  of  two  marks  fixed  on  the  sides  of  the  bar,  one 


1 6  GAS   AND   GAS    METERS 

in  front  of  and  one  behind  the  candles.  As  the  beam  of  the 
balance  projects  far  within  the  bar  and  consequently  the  scale 
is  hidden  from  view,  some  other  arrangement  had  to  be  made  for 
noting  the  swing  of  the  balance.  This  was  very  satisfactorily 
settled  by  the  use  of  a  pointer  about  5  inches  long  fastened  per- 
pendicularly to  the  balance  at  a  point  above  the  knife  edges. 
As  the  balance  swings,  this  pointer  passes  a  thin  line  across  a  small 
open  space  joining  the  ventilation  hole,  and  thus  not  only  may  the 
end  point  be  very  accurately  read,  but  also  the  movements  of  the 
balance  may  be  watched  without  stooping.  While  making 
readings  the  door  in  front  of  the  candles  is  closed  to  prevent 
drafts,  and  a  black  velvet  curtain  is  hung  behind  the  gas  flame  to 
exclude  external  light  and  prevent  reflection. 

The  actual  operation  of  testing  is  performed  in  exactly  the 
same  manner  as  with  a  stationary  photometer,  but  in  making  the 
corrections  there  are  one  or  two  changes.  The  correction  for 
temperature  is,  with  a  dry  meter,  i  per  cent  for  every  5  degrees, 
instead  of  i  per  cent  for  4  degrees,  as  with  the  wet  meter;  and  a 
correction  must  be  made  for  the  error  of  the  meter.  The  latter 
should  be  tested  as  often  as  possible  against  a  standard  wet  meter, 
and  the  percentage  error  thus  found  carried  into  the  candlepower 
calculations.  Thus,  if  the  meter  is  found  to  be  slow,  it  means 
that  it  is  registering  less  gas  than  is  actually  passing.  Then  the 
candlepower  as  found  is  higher  than  it  should  be,  since  it  is 
obtained  by  burning  more  gas  than  is  shown  by  the  dial  of  the 
meter.  Hence  for  a  slow  meter  the  percentage  correction  for 
error  of  the  meter  will  be  minus,  and  for  a  fast  meter,  plus.  The 
reason  for  the  change  in  the  temperature  correction  is  that  with 
a  dry  meter  the  tension  of  aqueous  vapor  does  not  enter  into  the 
question  as  it  does  with  a  wet  meter. 

There  are  several  unsatisfactory  features  connected  with  the 
instrument  just  described,  most  of  which  may,  however,  be  easily 
eliminated.  In  the  first  place  the  base  on  which  the  photometer 
rests  while  in  use  is  too  narrow,  rendering  it  unstable  and  pecul- 
iarly susceptible  to  jarring.  The  apparatus  is  rather  heavy  to 
manage,  and  because  of  this  and  of  the  narrowness  of  the  ends  of 


PHOTOMETER   AND   ACCESSORIES  I/ 

the  trunk,  it  is  severely  handled  by  baggagemen.  The  outside 
of  the  box  is  thus  often  in  need  of  repairs,  while  the  contents,  with 
the  exception  of  the  meter,  are  very  seldom  seriously  injured. 

The  sight  box  is  of  necessity  set  close  to  the  bottom  of  the  bar, 
and  thus  the  readings  are  liable  to  be  affected  by  reflection  from 
dust  along  the  bed  of  the  photometer.  Moreover,  the  bar  is  so 
constructed  that  it  is  somewhat  difficult  to  keep  the  interior  clean, 
although  this  may  and  should  be  done.  There  is  no  governor  or 
pressure  gauge  provided,  and  these,  of  course,  are  desirable, 
although  not  absolutely  essential. 

The  above  objections,  together  with  three  others,  are  applied 
by  the  American  Gas  Institute  to  portable  photometers  in  gen- 
eral. The  three  additional  reasons  for  complaint  are  as  follows: 

(1)  The  photometer  is  closed  and  is  thus  supplied  with  vitiated 
air;    also  under  this    condition  such    air   as    the    flames    get  is 
supplied    through    small    crevices    and    accompanied    by    drafts. 

(2)  Rubber    tubing    is    often    used    which    reduces    the    candle- 
power.     (3)  The  photometer  is  usually  set  up  in  any  place  that 
comes  handy,  and  hence  has  no  proper  ventilation,  temperature 
or  protection  against  drafts. 

With  the  portable  instrument  above  described  there  is  no  rubber 
tubing  used,  its  place  being  taken  by  a  flexible  metallic  tubing  made 
of  iron  and  so  packed  with  rubber  that  the  latter  never  comes  in 
contact  with  the  gas.  This  is  a  very  essential  point,  as  experiments 
by  the  writer  have  shown  a  loss  of  candlepower  reaching  as  high  as 
14  per  cent,  due  to  the  use  of  rubber  tubing.  Such  loss  is  by  no 
means  confined  to  old  samples  of  tubing,  for  several  lengths  of  new 
and  expensive  rubber  hose  showed  a  similar  loss.  The  metallic 
tubing  may  be  coiled  in  about  the  same  space  that  would  be  occu- 
pied by  the  rubber,  and  thus  far  has  given  excellent  satisfaction.  It 
may  be  obtained  of  the  New  York  Flexible  Metallic  Hose  and 
Tubing  Company  of  New  York  City,  at  a  price  of  about  nine  cents 
a  foot. 

Objection  No.  i,  regarding  vitiated  air,  does  not  seem  to  apply 
to  the  instrument  described,  as  the  air  supply  is  more  than  sufficient 
for  both  gas  and  candles ;  and  considering  the  size  of  the  openings 


1 8  GAS   AND    GAS    METERS 

for  entering  air  and  escaping  products  of  combustion,  it  can  hardly 
be  said  that  the  air  is  supplied  through  small  crevices  and  conse- 
quently accompanied  by  drafts.  Objection  No.  3  would  seem  to 
be  more  a  fault  of  the  operator  than  of  the  instrument,  but  it  remains 
a  serious  charge  against  the  use  of  portable  photometers  in  general, 
and  one  which  will  not  be  easily  corrected. 

Mr.  Charles  D.  Jenkins,  State  Gas  Inspector  of  Massachusetts, 
who  has  used  and  studied  the  portable  photometer  for  twenty- 
five  years,  has  recently  devised  a  new  one  which,  while  following 
the  same  general  lines  as  the  old  type,  has  many  improvements 
which  tend  to  dimmish  error  and  to  render  the  operation  and  trans- 
portation more  easy  and  safe. 

The  outer  trunk  is  of  leatheroid,  well  reenforced  by  steel.  Inside 
of  this,  and  of  nearly  the  same  size,  is  a  box  of  one-half-inch  material 
in  which  are  packed  the  bar,  meter  and  accessories. 

The  system  of  retaining  the  smaller  articles  in  place  is  by  straps, 
rather  than  by  thumb  nuts,  but  there  is  some  question  whether  this 
is  any  improvement.  The  inner  box  is  34  inches  by  i6|  inches  by 
12  j  inches,  thus  affording  a  much  broader  and  more  stable  base  for 
the  photometer  when  set  up.  The  purpose  of  the  leatheroid  case 
is  to  protect  the  apparatus  from  jarring  during  shipment  and  to 
save  repairs  on  the  external  part.  At  the  same  time,  and  because 
of  this  added  protection,  it  has  been  possible  to  reduce  the  weight  of 
the  whole  apparatus  considerably,  by  using  thinner  stock  and  little 
or  no  steel,  or  other  reinforcements. 

The  burner  board,  instead  of  setting  within  the  trunk,  is  held  by 
two  steel  arms,  which  project  a  fixed  distance  beyond  the  trunk. 
This  tends  to  improve  the  ventilation,  as  does  also  a  circular  hole, 
which  is  cut  in  the  interior  box  below  its  junction  with  the  bar,  and 
less  than  a  foot  above  the  floor.  It  is  quite  possible  that  this  open- 
ing may  give  rise  to  drafts,  but  thus  far  such  an  effect  has  not  been 
noticed.  The  ventilator  above  the  candles  is  covered  by  a  cap 
exactly  similar  to  those  placed  on  closed-bar  stationary  photometers. 
While  the  air  supply  for  the  flames  is  not  at  all  diminished  by  this 
device,  any  possibility  of  external  light  entering  the  bar  at  this  point 
is  precluded. 


PHOTOMETER  AND   ACCESSORIES  19 

The  bar,  instead  of  breaking  in  the  center,  does  so  at  a  point 
about  2  feet  and  8  inches  from  the  end  supported  by  the  cover. 
This  is  a  distinct  improvement,  as  it  removes  the  joint  beyond 
reach  of  the  sight  box,  and  in  the  older  forms  the  sliding  of  the  sight 
box  over  the  joint  gave  rise  to  a  jar  which  invariably  caused  flicker- 
ing of  the  candles. 

A  similar  instrument  is  being  constructed  for  use  in  New  York 
State,  and  while  the  cost  is  about  $25  greater  than  that  of  the  pre- 
ceding form,  it  is  believed  that  both  time  and  money  will  be  saved 
in  the  long  run,  while  the  accuracy  and  efficiency  are  doubtless 
somewhat  increased. 

Various  other  forms  of  photometers  have  been  devised,  some  of 
which  are  in  use  to-day;  and  a  few  types  are  briefly  described  below? 
for  while  most  of  these  instruments  are  intended  more  for  scientific 
than  for  practical  use,  the  principles  involved  may  at  any  time  be 
applied  to  the  manufacture  of  a  photometer  which  shall  fulfill  all 
requirements  and  be  satisfactory  for  general  use. 

The  Wild  Flicker  photometer  differs  from  the  ordinary  photom- 
eter in  that  the  disc,  which  is  thin,  circular,  and  made  of  some 
white  material,  one-half  being  opaque  and  reflecting,  while  the 
other  half  is  translucent  and  diffusing,  revolves  on  its  center  and 
is  viewed  by  the  agency  of  a  mirror  and  telescope.  As  the  disc 
revolves  an  unequal  illumination  of  the  two  halves  will  cause  a 
distinct  flicker  to  be  seen  every  time  the  line  separating  the  halves 
crosses  the  field  of  vision,  and  this  flicker  will  totally  disappear 
when  the  halves  are  equally  illuminated.  The  disc  is  made  to 
revolve  by  the  use  of  a  small  motor. 

Selenium  photometers  depend  for  their  action  on  the  fact  that 
selenium  conducts  electricity  to  a  degree  dependent  on  the  inten- 
sity of  the  illumination  thrown  upon  it.  An  instrument  embody- 
ing this  principle  is  manufactured  at  the  Elektromechanische 
Werkstatte  of  Mainz.  The  selenium  cell  is  placed  between  the 
two  sources  of  light  which  are  being  compared,  and  is  connected  in 
series  with  a  battery  and  a  milli-ampere  meter.  When  both  sides 
of  the  cell  are  equally  illuminated  there  is  no  current.1  Whether 

1  Journal  of  the  American  Chemical  Society  Abstracts,  March  20,  1908. 


20  GAS   AND    GAS    METERS 

this  is  the  best  of  the  selenium  photometers  or  not,  the  author  is 
unable  to  say,  as  these  instruments  are  as  yet  rare;  but  it  will  serve 
to  give  some  idea  of  their  general  action.  It  is  doubtful  whether 
they  will  ever  become  of  practical  importance,  for  the  sensitiveness 
of  selenium  to  light  seems  to  be  variable  and  uncertain,  and  the 
cells  subject  to  deterioration.1 

A  type  of  grating  photometer  has  recently  been  devised  which 
is  claimed  to  be  extremely  accurate.  The  object  used  to  cast  a 
shadow  is  a  grating  of  narrow  mesh,  the  wires  of  which  are  inclined 
at  angles  of  45  degrees  to  the  vertical.  The  two  sources  of  light 
to  be  compared  are  disposed  on  the  same  horizontal  plane  on  the 
one  side  of  the  vertically  supported  grating,  while  on  the  other  side 
is  a  screen  of  matt  glass.  The  lights  therefore  cast  a  pair  of  images 
of  the  grating  on  the  screen,  and  the  distance  between  screen  and 
grating  is  so  arranged  that  the  individual  bars  of  shadow  are  at 
the  same  distance  apart.  The  angles  at  which  the  light  rays 
impinge  on  the  grating  and  the  screen  are  also  so  arranged  that 
the  right  eye  of  the  observer  is  in  the  axis  of  the  rays  proceeding 
from  the  left-hand  light,  and  the  left  eye  in  the  axis  of  those  from 
the  right-hand  light.  This  causes  each  eye  to  see  only  one  set  of 
shadows  distinctly,  a  stereoscopic  effect  being  produced.  When 
the  two  images  coalesce  the  observer  seems  to  see  a  single  set  of 
bars  in  space,  the  components  of  which  appear  to  lie  in  different 
planes  until  the  two  lights  have  been  so  adjusted  as  to  cast  equal 
illumination  on  the  grating.  By  the  employment  of  suitable 
reflecting  mirrors  or  prisms,  the  whole  optical  system  can  be  erected 
on  a  bar  photometer.2  It  is  rather  curious  in  this  connection  to 
note  how  this,  one  of  the  most  recent  of  photometers,  goes  back  in 
principle  to  one  of  the  earliest  instruments,  that  devised  by  Count 
Rumford  in  1792,  in  which  the  illuminating  power  was  determined 
by  casting  the  shadow  of  a  slender  rod  upon  a  screen  and  com- 
paring the  distances  of  standard  and  gas  from  the  screen  when  the 
shadows  cast  by  the  two  were  of  equal  intensity. 

The  Jet  photometer  is  not  a  photometer  in  the  strict  sense  of 

1  Gooch  and  Walker,  Outlines  of  Inorganic  Chemistry,  Pt.  2,  p.  279. 
.    2  Journal  of  Gas  Lighting,  April  14,  1908. 


PHOTOMETER   AND   ACCESSORIES  21 

the  word;  it  may  be  considered  as  a  specific  gravity  instrument, 
and  will  therefore  be  described  in  a  later  chapter. 

Many  other  photometers  have  appeared,  in  print  at  least,  during 
recent  months,  but  as  these  have  not  as  yet  proved  their  practical 
value,  they  will  not  be  described  here.  The  reader  who  is  interested 
in  them,  however,  should  consult  the  Journal  of  Gas  Lighting  for 
May  7,  1907,  and  June  2,  1908,  the  American  Gas  Light  Journal, 
June  29,  1908,  the  Progressive  Age,  Feb.  i,  1908,  etc. 

Meter.  The  Committee  of  the  American  Gas  Institute  recom- 
mends l  the  use  of  a  wet  photometer  meter,  having  a  capacity  of 
one-twelfth  of  a  cubic  foot  per  revolution,  and  from  the  author's 
experience  in  New  York  State  this  would  seem  to  be  the  meter 
which  is  coming  most  generally  into  use  in  connection  with  photo- 
metric work.  The  only  advantage  of  this  meter  over  the  one 
making  one-tenth  of  a  cubic  foot  per  revolution,  is  that  it  somewhat 
simplifies  the  calculations;  since,  if  the  meter  makes  one  revolution 
of  one-twelfth  of  a  cubic  foot  per  minute,  the  gas  is  being  consumed 
at  the  rate  of  5  feet  per  hour.  Such  a  meter,  if  bought  separately, 
will  cost  $50  and  will,  if  properly  cared  for,  render  accurate  and 
lasting  service.  The  care  of  the  meter  and  apparatus  in  general 
will  be  described  in  a  succeeding  chapter. 

Governor.  The  use  of  two  governors  is  an  aid  to  accurate  work; 
these  should  be  placed,  the  one  on  the  inlet  and  the  other  on  the 
outlet  of  the  photometer  meter.  The  inlet  governor  is  for  the 
purpose  of  securing  a  uniform  pressure  on  the  gas  in  the  inside  of 
the  meter  drum,  while  the  outlet  governor  serves  to  still  further 
reduce  the  pressure  of  the  gas  before  it  reaches  the  burner  and 
also  to  compensate  for  fluctuations  in  pressure  produced  as  the 
meter  partitions  dip  into  the  water.  Two  kinds  of  governors,  the 
wet  and  the  dry,  are  in  common  use.  The  latter,  while  not  quite  as 
delicate  as  the  former,  is  recommended  for  general  use  for  three 
reasons:  First,  it  requires  less  care;  second,  it  does  not  call  for  the 
use  of  water,  which  must  be  added  to  the  wet  governor  from  time 
to  time,  and  which  after  each  such  addition  must  be  saturated  with 
the  gas  under  test  before  correct  results  can  be  obtained;  third, 

1  Proceedings  of  American  Gas  Institute,  October,  1907. 


22  GAS   AND    GAS   METERS 

the  dry  governor  allows  changes  in  candlepower  to  be  more  quickly 
noted  because  the  water  in  the  wet  governor  may  absorb  or  give 
off  illuminants  if  conditions  are  varied. 

Disc.  A  good  disc  is  one  of  the  photometrist's  most  important 
allies,  and  a  large  measure  of  his  success  and  accuracy  will  depend 
on  his  choice  of  this  feature.  There  are  three  types  on  the  market 
which  seem  to  have  met  with  considerable  favor,  —  the  Lummer 
Brodhun,  the  Leeson  contrast  disc,  or  the  disappearing  star,  and 
the  Bunsen  disc.  Of  these  the  first  is  accurate  but  fatiguing  to 
the  eye;  the  second  is  said  to  be  equally  accurate  and  less  tiresome; 
the  third,  if  well  made,  is  very  easy  to  read  and  is  simple  and 
cheap.  The  author  has  had  a  rather  wide  experience  with  discs 
of  the  disappearing  star  type,  and  as  a  result  feels  that  he  can 
recommend  them  for  general  use.  There  has  been  considerable 
difficulty,  however,  in  securing  a  star  disc  which  would  read  the 
same  on  both  sides,  and  very  many  of  the  discs  inspected  were 
incapable  of  furnishing  accurate  results,  even  in  expert  hands. 
The  committee  of  the  American  Gas  Institute  (whose  report  is 
quoted  so  often  in  this  volume  for  the  simple  reason  that  in  the 
author's  mind  it  is  the  ablest  and  most  thorough  utterance  on  the 
science  of  photometry  which  has  been  delivered  in  this  country) 
recommends  the  Leeson  contrast  disc,  and  thus  confirms  the 
author's  opinion;  but  the  Bunsen  disc  is  very  highly  regarded  by 
such  authorities  as  Mr.  Jenkins,  of  Massachusetts,  and  will,  if 
carefully  chosen,  give  most  satisfactory  results. 

Candle  Balance.  The  candle  balance  used  in  a  photometer 
should  be  set  firm  and  level  in  the  proper  chamber.  It  is  well  to 
have  its  position  permanently  fixed;  this  may  be  accomplished  by 
having  a  circular  socket  let  into  the  floor  of  the  chamber  into  which 
the  base  of  the  balance  fits  tightly.  There  should  be  some  means 
provided  for  raising  or  lowering  the  beam  and  pan,  which  should 
also  be  capable  of  being  moved  a  little  backward  or  forward  in 
order  to  align  the  candles.  The  knife  edges  and  bearings  must 
be  accurately  made  and  fitted;  the  balance  should  swing  freely 
and  quickly  and  respond  readily  to  a  one-grain  weight.  The  candle 
holder  should  be  so  constructed  that  candles  may  be  easily  inserted 


PHOTOMETER  AND  ACCESSORIES  23 

or  removed  without  their  being  gouged  or  otherwise  damaged, 
and  at  the  same  time  the  candles  must  be  firmly  held  in  place. 
Both  a  rough  and  a  fine  adjustment  should  be  provided. 

Sight  Box.  The  sight  box  must  slide  in  the  gallery  easily  and 
without  jar.  It  must  be  easy  to  open,  so  that  mirrors  and  disc  may 
be  kept  clean;  this  purpose  is  served  if  the  entire  top  of  the  box  is 
hinged.  The  disc  should  give  a  sharp  end  point  and  should  be 
reversible.  A  pair  of  good  mirrors  will  greatly  facilitate  the  work. 


CHAPTER  II. 
STANDARDS  AND  BURNERS. 

ON  no  part  of  the  photometric  outfit  have  so  much  time  and 
research  been  expended  as  on  the  invention  and  testing  of  standards, 
and  up  to  the  present  time  only  one  has  been  produced  which  is 
not  subject  to  adverse  criticism.  The  author  has  before  him 
descriptions  of  some  fifty  different  types  of  proposed  standards, 
only  about  fifteen  of  which,  however,  have  ever  seen  really  active 
service.  It  is  not  within  the  scope  of  this  work  to  describe  or  even 
mention  all  of  these  various  types,  since  most  of  them  are  either 
obsolete,  inaccurate,  or  impracticable  for  general  use.  Likewise 
we  shall  not  go  into  the  question  of  theoretical  or  of  primary 
standards,  however  interesting  and  important  the  subject  may  be, 
for  it  could  be  of  no  service  to  the  practical  gas  man  or  photom- 
etrist.  It  seems  advisable,  however,  to  treat  rather  fully  of  the 
history,  manufacture  and  use  of  such  standards  as  are  in  practical 
service  to-day,  in  order  that  the  reader  may  understand  the  advan- 
tages and  disadvantages  of  each.  There  are  but  six  of  these,  —  the 
lo-candle  Pentane  lamp,  the  Hefner,  Carcel,  and  Elliott  lamps, 
the  Edgerton  slit  and  candles. 

Candles.  The  founder  of  the  gas  industry,  Murdoch,  seems 
also  to  have  been  a  pioneer  in  the  field  of  standards,  for  in  1808 
he  noted  that  the  light  from  tallow  candles  varied,  and  therefore 
specified  that  the  latter  should  weigh  six  to  the  pound  and  should 
burn  at  the  rate  of  175  grains  per  hour.  This  tended  to  produce 
uniformity,  but  the  tallow  candle  was  not  adapted  to  accurate 
work,  and  was  succeeded  by  the  wax  candles.  These  latter  were 
used  as  early  as  1824,  but  not  until  1849  were  they  made  a  legal 
standard  in  England  by  act  of  Parliament.  Undoubtedly  im- 
provement had  been  made  over  the  tallow,  but  wax  candles  proved 
unsatisfactory,  as  Dr.  Letheby,  then  chemist  of  the  city  of  Lon- 

24 


STANDARDS   AND   BURNERS  25 

don,  reports  that  the  consumption  of  wax  was  irregular  and  that 
it  was  impossible  to  determine  when  they  were  burning  properly. 
Attempts  were  made  to  introduce  paraffin  for  the  manufacture  of 
standard  candles  in  1852,  when  Lewis  Thompson  declares  it  to 
be  superior  to  wax  or  sperm  because  it  is  readily  tested  as  to 
purity,  and  its  composition  is  easily  fixed  and  determined  the 
world  over.1  This  plea,  however,  never  brought  paraffin  to  the 
front  in  England,  although  in  Germany  it  was  adopted  as  stand- 
ard in  1872,  and  definite  specifications  issued  regarding  its  use. 
Tests  of  these  candles  by  Lummer  and  Brodhun  showed  them 
to  be  unsatisfactory  in  that  the  top  of  the  flame  split  into  three 
parts  and  that  the  flame  smoked.  The  directions  for  using  these 
candles  required  that  the  readings  should  be  made  when  the 
flame  was  50  mm.  high.  This  evidently  assumed  a  fixed  rela- 
tion between  flame  height  and  intensity,  and  when  it  was  proved 
that  such  a  relation  did  not  exist,  the  accuracy  of  the  method 
was  seriously  impugned. 

Stearine  candles  have  been  tried  in  two  forms,  one  the  Munich 
candle,  and  the  other  the  French  Bougie  de  1'Etoile.  The  former 
had  a  short  and  rather  uneventful  life,  going  out  of  use  in  1860, 
while  of  the  latter  the  Journal  of  Gas  Lighting,  in  1859,  says: 
"For  uniformity  and  steadiness  of  light  the  stearine  candle  sold 
in  France  under  the  name  of  Bougie  de  1'Etoile  far  surpasses  the 
ordinary  sperm  candle."  The  Bougie  was  for  some  time  stand- 
ard in  France,  and  Durand  states  that  the  Carcel  lamp,  the 
recognized  standard  in  that  country  to-day,  should  always  be 
tested  against  the  stearine  candle  before  using. 

Sperm  candles  as  standards  were  first  used  as  a  substitute  for 
wax  in  1852,  and  in  1860  were  legalized  by  the  Metropolis  Gas 
Act.  Undei  this  act  very  careful  specifications  were  issued  for 
the  manufacture  of  these  candles;  the  wick  was  to  consist  of 
three  strands,  each  of  18  threads;  there  were  to  be  32  to  34  plaits 
in  4  inches  of  the  wick  when  extended  by  a  pull  just  sufficient  to 
straighten  it  out.  The  wick  after  steeping  and  drying  was  to 
weigh  not  less  than  6  nor  more  than  6J  grains  for  each  12  inches. 

1   Journal  of  Gas  Lighting,  June  23,  1908. 


26  GAS   AND    GAS    METERS 

The  weight  of  the  ash  from  10  wicks  after  treatment  with  water 
was  to  be  0.025  grain.  The  spermaceti  used  must  have  a  melt- 
ing point  of  from  112  to  115°  F.,  while  that  of  the  finished  material 
would  be  slightly  higher  on  account  of  the  3  to  4^  per  cent  of 
beeswax  which  was  added  to  prevent  crystallization  of  the  sperm. 
If  a  4o-grain  brass  weight  were  attached  to  the  wick,  and  the 
candle  floated  in  water  at  60°  F.,  taper  end  down,  it  should  float 
with  a  2-grain  weight  placed  on  top  and  sink  with  a  4-grain 
weight.  It  seems  that  the  manufacturers  found  it  impossible  to 
comply  with  these  directions,  and  Dr.  Love,  of  New  York,  after 
a  careful  investigation,  found  that  with  the  candles  which  he 
tested  not  one  of  the  above  specifications  was  fulfilled.  This 
may,  in  some  measure,  account  for  the  disfavor  into  which  these 
candles  have  fallen,  for  there  is  no  disguising  of  the  fact  that 
candles  to-day  are  not  satisfactory  as  standards,  although  they 
are  used  more  frequently  than  any  other  form.  The  bare  fact 
is  apparent  to  anyone  who  has  used  candles  extensively,  but  the 
reasons  may  not  be  quite  as  clear.  Hornby  in  his  Gas  Manu- 
facture says:  "Slight  variations  in  the  quality  of  the  sperm  and 
in  the  method  of  admixture  (for  4  to  5  per  cent  of  beeswax  is 
added  to  keep  the  sperm  from  crystallizing),  and  changes  in  pro- 
cess of  manufacture,  will  sometimes  tend  to  slightly  alter  the 
results  obtained  with  such  candles. 

"  The  weak  point  of  the  candle,  however,  is  the  wick,  the  rough- 
ness or  smoothness  of  which,  and  its  curvature  during  burning 
causing  extraordinary  variations  in  the  light  emitted  by  it,  even 
supposing  that  the  wicks  could  be  made  absolutely  uniform, 
the  twist  of  the  thread  kept  constant,  and  the  same  amount  of 
strain  placed  upon  them  during  the  making  of  the  candle." 

Even  this  does  not  include  all  of  the  charges  brought  against 
candles.  They  are  said  to  be  unreliable  even  when  made 
according  to  the  most  exacting  specifications;  they  are  very 
strongly  influenced  by  changes  in  atmospheric  conditions,  such  as 
heat,  moisture,  and  the  presence  of  carbonic  acid;  and  any  cor- 
rection for  these  factors  is  extremely  difficult  if  not  at  the  present 
day  impossible  in  the  case  of  the  average  gasworks. 


STANDARDS   AND   BURNERS  2/ 

That  the  light  emitted  by  candles  is  affected  by  altitude  is 
proven  by  the  experiment,  in  1859,  of  Frankland  and  Tyndal, 
who  burned  a  candle  on  the  summit  of  Mont  Blanc,  where  the 
atmospheric  pressure  was  only  16.4  inches,  and  found  that  the 
sperm  was  being  consumed  at  the  normal  rate,  but  that  the  flame 
was  entirely  non-luminous.  To  illustrate  the  amount  of  the 
error  introduced  by  one  of  the  above  causes,  a  table  will  be  found 
in  the  appendix  showing  the  effect  of  temperature  on  candle- 
power. 

Now,  while  admitting  all  of  the  weaknesses  mentioned  above, 
and  without  being  desirous  of  being  regarded  as  an  advocate  of  the 
candle  as  the  best  standard  (which  it  most  assuredly  is  not),  the 
author  feels  that  a  very  considerable  part  of  the  curse  which  rests 
upon  candles  is  due  to  the  improper  use  of  them;  and  that  while 
they  are  not  accurate  enough  to  serve  as  an  unchangeable  standard, 
their  cheapness,  simplicity,  availability  and  adaptability  recommend 
them  in  many  cases  where  a  more  accurate  standard  would  be 
impracticable. 

These  opinions  are  based  on  long-continued  observations  of  the 
use  of  candles  by  a  very  large  number  of  gas  companies,  as  well  as 
by  many  of  the  inspectors  appointed  by  various  state  and  local 
governments,  and  it  is  only  fair  to  admit  that  if  the  Pentane  lamp 
or  any  other  standard  were  used  with  the  same  calm  disregard  for 
the  most  vital  principles  governing  their  operation,  as  is  shown  in 
the  daily  use  of  the  candle,  its  accuracy  would  be  utterly  unreliable. 

Moreover,  the  candle  is  the  only  standard  which  can  be  used 
with  a  portable  photometer,  and  this  fact  alone  will  compel  its 
employment  in  some  cases,  and  more  especially  in  the  work  of  gov- 
ernment supervision',  until  some  equally  portable  and  more  accurate 
substitute  is  found.  The  precautions  necessary  to  be  observed  in 
the  use  of  candles  will  be  fully  dealt  with  in  a  later  chapter,  but 
before  leaving  the  subject,  there  are  two  definitions  which  should 
be  placed  before  the  reader,  and  which  would  seem  to  belong  under 
this  heading. 

The  unit  of  light  for  gas  is  "the  average  light,  measured  in  a 
horizontal  direction,  given  by  Parliamentary  sperm  candles  pre- 


28 


GAS   AND    GAS   METERS 


scribed  by  the  British  Metropolis  Gas  Act  of  1860,  said  candles  to 
be  six  to  the  pound  and  burning  120  grains  per  hour.  If  custom 
is  to  be  followed,  the  unit  of  light  as  understood  to-day  by  the 
illuminating-gas  industries  of  the  United  States  is  one-tenth  of 
the  Harcourt  lo-candle  Pentane  lamp."  1 

Mr.  Grafton  gives  the  following  definition  of  the  light  of  a  candle 
which  it  is  well  to  bear  in  mind:  "The  light  of  one  English  candle 
is  the  amount  of  light  emitted  and  maintained  for  at  least  one  hour 
after  maturing,  from  the  combustion  of  120  grains  of  sperm  fed  by 
a  definite  sized  wick  in  a  quiet  but  pure  atmosphere." 


5.     Carcel  Lamp. 


The  Carcel  lamp  is  the  oldest  candlepower  standard  which  is  in 
use  to-day,  having  been  invented  by  Carcel  some  no  years  ago.  It 
is  official  in  Paris  and  is  accepted  throughout  France,  although  not 
widely  used  outside  of  that  country,  and  very  rarely  seen  in  the 
United  States.  It  consists2  of  an  Argand  burner  (Fig.  5),  with 

1  Journal  of  the  Franklin  Institute,  March,  1908. 

2  Journal  of  Gas  Lighting,  June  23,  1908. 


STANDARDS   AND    BURNERS 


29 


wick  and  chimney,  the  oil  being  forced  by  pumps  through  the  cen- 
tral pipe  to  the  burner  above.  These  pumps,  of  which  there  are 
three,  empty  into  a  common  space  and  are  operated  by  clockwork 
in  the  base.  An  overflow  of  the  surplus  oil  is  always  maintained, 
so  that  the  wick  draws  its  supply  from  a  constant  head,  thus  insur- 
ing uniform  conditions.  Colza,  or  rape-seed  oil  is  used,  and  the 
rate  of  consumption  maintained  at  42  grams  per  hour,  regardless 
of  the  height  of  the  flame,  as  at  that  rate  there  is  the  least  variation 
in  candlepower  for  a  given  variation  in  oil  consumed.  The  wick  is 
the  delicate  part  of  the  lamp  and  should  be  frequently  changed, 
the  rules  for  official  testing  in  Paris  requiring  a  new  wick  for  each 
test.  While  opinions  vary  greatly  as  to  the  accuracy  of  this  lamp, 


Fig.  6.     Hefner  Lamp. 

there  is  no  question  but  that  it  is  sufficiently  exact  for  practical 
work.  It  is  not  to  be  recommended  for  the  latter  purpose,  how- 
ever, for  several  reasons,  of  which  it  will  be  necessary  to  give  but 
one,  namely,  that  simpler,  cheaper,  sufficiently  accurate  instru- 
ments are  on  the  market,  which  can  be  put  in  the  hands  of  a  works 
foreman  or  a  clerk  in  the  office,  and  trustworthy  results  secured 
thereby. 

The  Hefner  lamp  was  brought  out  in  1884.  It  consists  *  of  a 
small  lamp  (Fig.  6),  with  a  wick  made  of  cotton  threads  (15  to  20 
in  number)  laid  straight  until  the  total  size  of  the  wick  is  just  suffi- 
cient to  fill  the  wick  tube,  which  is  8  mm.  in  diameter,  without 

1  Journal  of  Gas  Lighting,  July  7,  1908. 


30  GAS   AND    GAS   METERS 

squeezing.  The  lamp  is  of  brass  throughout,  with  the  exception  of 
the  wick  tube,  which  is  made  of  German  silver  to  avoid  corrosion. 
For  the  same  reason  the  walls  and  interior  should  be  well  plated. 

The  wick  is  operated  by  a  worm  gear  which  actuates  two  spur 
wheels.  When  not  in  use  the  wick  tube  is  kept  covered  by  a  cap. 
The  height  of  the  flame  should  be  40  mm.  and  must  be  exactly 
adjusted. 

The  fuel  consumed  is  amyl  acetate,  a  colorless,  chemical  com- 
pound, prepared  commercially  by  the  distillation  of  amyl  alcohol 
with  a  mixture  of  common  or  ethyl  alcohol,  sulphuric  acid  and 
potassium  acetate.  The  finished  product  is  liable  to  contain  small 
quantities  of  water  and  alcohol,  but  these,  in  the  amounts  in  which 
they  ordinarily  occur,  have  no  appreciable  effect  on  the  luminous 
intensity  of  the  flame,  although  they  do  seriously  influence  its 
stability. 

Amyl  acetate  may  be  readily  obtained  for  about  $6.00  per 
gallon,  and  the  cost  of  a  certified  Hefner  lamp  is  $27.00. 

This  lamp  is  largely  used  in  Germany  and  in  a  few  cases  in  the 
United  States,  and  for  constancy  and  reproducibility  it  is  said  to 
be  the  equal  of  the  best  flame  standards.1  As  a  working  standard, 
however,  it  has  serious  defects.  In  the  first  place  the  flame  is  of 
reddish  color  and  consequently  difficult  to  compare  with  a  gas 
flame. 

Second,  the  value  of  the  Hefner  is  only  0.88  candle,  and  this  fact 
likewise  tends  to  increase  the  difficulty  of  reading  and  to  render 
the  results  less  accurate. 

Third,  the  flame  must  be  maintained  at  an  exact  height  of 
40  mm.  during  the  test,  and  this  can  hardly  be  done  without  the 
presence  of  two  observers,  one  to  make  readings  and  the  other  to 
watch  the  flame. 

Fourth,  the  lamp  must  be  operated  in  a  perfectly  quiet  atmo- 
sphere, since  the  flame  flickers  at  the  slightest  jar  or  draft,  such  as 
might  be  caused  by  the  walking  about  of  the  observer,  the  moving 
of  the  sight  box,  the  opening  or  closing  of  a  door  in  another  part  of 
the  building,  etc. 

1  Proceedings  of  American  Gas  Institute,  October,  1907. 


STANDARDS   AND   BURNERS  31 

Fifth,  the  setting  of  the  height  of  the  flame  at  40  mm.  is  not  as 
simple  as  it  sounds,  on  account  of  the  very  pointed  character  of 
the  flame  tip;  and  an  error  of  i  mm.  (or  0.04  inch)  in  setting  will 
cause  an  error  of  2.5  per  cent  in  the  light  emitted. 

From  a  consideration  of  all  these  facts  it  will  be  seen  that, 
however  satisfactory  the  Hefner  lamp  may  be  in  theoretical  work 
and  in  the  hands  of  skilled  observers,  it  is  not  to  be  recommended  as 
a  standard  for  works  use,  or  as  a  rule  for  purposes  of  governmental 
supervision. 

It  is  to  be  noted  that  all  of  the  standards  previously  described, 
together  with  the  Pentane  lamp,  have  been  the  invention  of 
foreigners.  This  is  not  surprising,  if  we  remember  the  length  of 
time  during  which  gas  has  been  in  service  and  under  supervision 
abroad,  and  that  only  since  1860  has  there  been  any  attempt  at 
such  regulation  in  the  United  States.  It  is  all  the  more  gratifying, 
therefore,  to  turn  to  the  discovery  of  a  standard  by  an  American. 

It  has  been  known  for  a  long  time  that  the  light  emitted  by  a 
kerosene  lamp  was  remarkably  uniform,  and  numerous  attempts 
have  been  made  to  devise  a  standard  which  should  use  kerosene 
as  a  fuel.  None  of  these  was  entirely  successful,  however,  until 
in  1906,  Dr.  A.  H.  Elliott,  of  the  Consolidated  Gas  Company  of 
New  York  City,  placed  his  standard  kerosene  lamp  on  the  market. 

This  is  of  the  student-lamp  form  (Fig.  7),  with  a  fiat  cotton  wick 
ij  inches  wide.  The  reservoir  is  of  sufficient  capacity  to  furnish 
oil  for  12  hours'  continuous  service,  and  is  supplied  with  the  usual 
valve  feed,  thus  insuring  a  constant  level  of  oil  at  all  times. 

The  chimney  used  is  the  No.  40  Macbeth  pearl  glass,  which  is 
10  inches  height,  1.75  inches  inside  diameter  at  the  top,  3  inches 
wide  outside  at  the  bottom,  and  about  4  inches  at  the  widest  part. 
An  adjustable  brass  screen  covering  the  upper  part  of  the  flame 
is  supported  on  two  uprights  which  are  riveted  to  the  burner  shell. 
This  screen  opening  is  made  seven-eighths  inch  over  the  crown 
of  the  cap,  and  ij  inches  between  the  side  wings. 

The  wick  in  use  is  trimmed  to  i  inch  in  width,  the  corners  being 
cut  off  equally  on  each  side  from  one-quarter  inch  on  the  top 
edge  to  one-half  inch  on  the  side;  this  is  done  to  prevent  the 


GAS    AND    GAS    METERS 


ends  from  throwing  out  long,  smoky  tails  which  might  crack  or 
smoke  the  chimney.  The  consumption  of  fuel  is  40  grams  per 
hour,  and  the  oil  recommended  is  known  as  Pratt's  Astral  oil, 
though  other  grades  may  be  used. 


Fig.  7.     Elliott  Lamp. 

The  lamp  gives  under  the  most  favorable  conditions  a  light 
equal  to  10  candlepower,  although  in  many  cases  which  have  come 
under  the  author's  personal  notice  it  has  been  impossible  to  obtain 
quite  this  figure. 


STANDARDS    AND    BURNERS 


33 


The  advantages  of  this  lamp  as  a  working  standard  are  many. 
It  is  cheap,  costing  only  $25.  The  fuel  used  may  be  obtained 
anywhere,  is  very  uniform  in  quality,  is  safe,  and  costs  but  15  to 
18  cents  per  gallon.  The  glass  of  the  chimney  is  relatively  distant 
from  the  flame,  and  thus  is  less  liable  to  fouling.  The  parts  are 
easily  replaceable  in  any  locality;  the  light  emitted  is  easy  to  com- 
pare with  gas,  the  flame  is  readily  adjusted  and  very  constant 
when  once  lit,  and  the  candlepower  of  the  lamp  is  high,  thus 
reducing  the  errors  of  observation. 

Tests  made  by  a  New  York  photometrist  at  the  request  of 
Dr.  Elliott  gave  a  remarkable  series  of  figures  in  which  the  readings 
with  the  lamp  did  not  vary  by  o.oi  candlepower  during  a  period 
of  4  hours.  The  author  was  not  able  to  duplicate  these  figures, 
but  secured  results  which  seemed  to  show  conclusively  that  after 
the  lamp  was  once  lighted  it  would  remain  sufficiently  constant 
for  practical  work  over  a  period  of  8  hours.  The  tests  in  the 
following  table  were  made  by  three  different  assistants,  each  trim- 
ming the  lamp  according  to  his  idea  of  the  directions. 

TEST  OF   ELLIOTT  LAMP.1 


Date. 

Time. 

C.   P. 

Date. 

Time. 

C.  P. 

Mav  24  
'Do  
Do  
Do 

9.40 

10.  40 
II.  40 

I    4.0 

8.74 
8.82 
8.76 
8  66 

July  17  

Do  
Do  
Do  

2.  00 

2-45 
4.  oo 
4.  4? 

8.64 

8-53 
8.69 
8.4* 

Do 

2    40 

8.76 

Tulv  10.  .  . 

IO.   Is 

8.  37 

Do 

•3    40 

8  67 

Do 

1  1     3O 

8  \\ 

Mav  25              .    . 

Q.  4O 

8.6? 

Do  

2.  00 

s.ls 

Do 

IO    dO 

8  70 

Do    

•3.  jr 

8  60 

Do 

1  1    4.O 

8  67 

Do  

4.  oo 

8.  c6 

Do 

12    4.O 

8  70 

Tulv   22  .. 

II.  3O 

7.  oo 

Mav  27 

1  1     ^O 

8  61 

Do  

I.  I<C 

7.84 

Do 

I     ^O 

8.61 

Do  

2.  OO 

7-  QO 

Do  
Julv  1  6  
'  Do 

4-30 

10.  30 

II    4s 

8.58 
8.29 

8    C2 

Do  

July  23  

Do    

4-30 

9-45 

IO     ^O 

7-94 
7.89 
7   80 

Do  
Do 

12.30 
I     3O 

<_>.  s,^ 
8.13 
8  si 

Do  
Do  

II.  30 
1  .  20 

8.  ii 
8.  io 

Do 

2    40 

8  38 

Do  

2.  3O 

7.68 

Do 

3T.O 

8  7=; 

Do  

T..  2O 

8.02 

Do  
Tulv  i7.. 

4-45 

10.  10 

8.22 
8.12 

Do  

4-3° 

8.02 

During  the  last  two  days  of  the  above  tests  the  wick  was  old  and  the  candlepower  of  the 
lamp  consequently  fell  off  to  a  marked  extent.  Its  constancy  also  seems  to  have  been 
somewhat  influenced  by  that  factor. 

1   For  results  with  the  five-candle  Elliott  lamp,  see  Tables  XI  and  XII  in  the  Appendix. 


34 


GAS   AND    GAS   METERS 


From  these  figures  it  will  be  seen  that  it  has  proved  difficult  to 
so  trim  the  wick  that  the  lamp  shall  give  the  same  candlepower 
on  different  days,  and  this  has  been  found  to  be  the  experience  of 
various  gas  companies  which  have  used  the  lamp.  This  trouble 
seems  to  arise  largely  from  the  fact  that  the  opening  in  the  screen 
has  been  made  so  large  as  to  take  in  the  greater  part  of  the  flame, 
and  consequently  slight  variations  in  trimming  have  either  caused 
some  of  the  blue  portion  of  the  flame  to  show  through  the  screen 
slit,  or  else  the  upper  corners  of  the  opening  were  not  completely 


Fig.  8.     Edgerton  Sleeve. 

filled  by  the  flame.  This  defect  has  been  remedied  by  the  inven- 
tor, who  has  now  reduced  the  candlepower  of  the  lamp  to  5,  and 
the  writer  is  assured  by  Dr.  Elliott  that  this  change  has  resulted 
in  even  greater  constancy  and  accuracy  than  is  exhibited  by  the 
locandle  standard. 


STANDARDS   AND  BURNERS  35 

Based  upon  a  principle  entirely  different  from  the  foregoing, 
the  Edgerton  standard,  which  uses  coal  or  water  gas  as  a  fuel, 
consists  of  a  Suggs  D  Argand  burner,  and  a  glass  chimney,  7 
inches  by  if  inches,  with  a  blackened  brass  sleeve  surrounding 
it.  In  the  front  of  this  sleeve  there  is  a  horizontal  slot  £f  of  an 
inch  high  and  of  sufficient  width  to  include  the  entire  diameter 
of  the  flame.  The  lower  edge  of  the  slot  is  seven-eighths  inch 
above  the  steatite  ring  of  the  burner,  and  if  the  flame  is  main- 
tained at  a  height  of  3  inches  the  most  luminous  zone  will  be 
included  in  the  slot.  The  portion  of  the  sleeve  directly  opposite 
to  the  slot  is  cut  away  to  avoid  reflections,  and  there  are  also 
windows  in  the  sides  to  enable  the  observer  to  properly  adjust  the 
flame.  The  radiant  center  is  nine-tenths  inch  in  front  of  the 
geometric  center,  and  this  fact  should  be  borne  in  mind  when 
standardizing  the  instrument. 

The  initial  cost  is  but  $3.75,  and  this,  together  with  its  relia- 
bility, ease  of  operation  and  the  fact  that  the  fuel  costs  almost 
nothing  and  is  always  at  hand,  renders  the  Edgerton  a  most  use- 
ful and  satisfactory  standard  for  works  use,  or  for  any  employment 
where  absolute  accuracy  is  not  required. 

There  are,  however,  certain  disadvantages  attendant  upon  its 
use.  Mr.  F.  N.  Morton,  in  his  superb  paper  on  the  History  of 
Photometric  Standards,  read  before  the  Illuminating  Engineering 
Society  in  February,  1908,  shows  the  wide  divergence  of  opinion 
which  exists  as  to  the  accuracy  of  this  standard,  and  states  that  in 
his  judgment  it  should  be  frequently  compared  with  candles, 
Pentane,  Hefner  or  some  other  form  of  standard.  The  general 
view  to-day  seems  to  be  that  if  the  gas  used  as  fuel  does  not  vary 
by  more  than  2  candlepower,  and  if  certain  simple  rules  are 
strictly  complied  with,  the  standard  will  be  accurate  within  0.2 
to  0.4  candlepower.  To  accomplish  this  the  chimney  must  be 
kept  clean  and  the  calibrated  section  of  it  must  always  be  turned 
towards  the  slot;  the  flame  height  must  be  maintained  nearly 
uniform,  and  the  factor  for  the  instrument,  which  lies  between 
4  and  7  candlepower,  must  be  frequently  verified  and  always 
redetermined  when  a  new  chimney  is  employed. 


36  CzAS   AND    GAS    METERS 

The  author  believes  that  this  and  the  Elliott  lamp  are  to  be 
strongly  recommended  for  works  use,  and  especially  in  cases  of 
small  plants  which  cannot  afford  to  employ  a  chemist  to  test  and 
purify  pentane,  etc.;  for  while  they  are  not  as  accurate  as  the 
Hefner,  Carcel  or  Harcourt  lamps,  they  are  much  cheaper  and 
more  easily  operated,  and  results  obtained  with  them  are  suffi- 
ciently near  to  the  truth  to  guide  the  manager  in  his  manufacture 
of  gas. 

This  standard  must  not  be  confused  with  the  Methven  screen, 
which,  while  in  many  particulars  similar  to  the  Edgerton,  is  for 
certain  fundamental  reasons  less  accurate  than  the  latter. 

The  Pentane  lamp  has  reached  a  pinnacle  never  attained  by 
any  other  standard,  namely,  it  is  to-day  without  an  opponent. 
For  this  reason  it  seems  advisable  to  devote  some  space  to  a  care- 
ful explanation  of  its  construction,  and  no  clearer  view  can  be 
obtained  than  is  given  by  the  following,  which  is  quoted  from 
Butterfield's  Extract  of  the  Referees'  method.  "Air  is  satu- 
rated with  pentane  vapor  by  passage  through  a  saturator  which 
is  about  two-thirds  filled  with  pentane,  and  the  air  gas  so  formed 
descends  by  its  gravity  to  a  steatite  ring  burner.  The  saturator 
is  184  mm.  square  and  38  mm.  deep,  and  contains  seven  par- 
titions soldered  to  its  top,  and  alternately  meeting  either  side,  and 
stopping  25  mm.  short  of  the  opposite  side.  The  air  is  thus  com- 
pelled to  pass  eight  times  across  the  saturator. 

"A  piece  of  India  rubber  tube  13  mm.  wide  internally,  conveys 
the  air  gas  from  the  saturator  to  the  burner.  The  air  inlet  pipe 
to  the  saturator  and  the  air  gas  outlet  are  provided  with  stop- 
cocks, and  the  height  of  the  flame  is  controlled  by  the  outlet 
cock. 

"A  brass  chimney  431  mm.  long,  30  mm.  inner  and  32  mm. 
outer  diameter,  is  placed  so  that  its  lower  end  when  cold  is  47  mm. 
above  the  steatite  burner.  This  chimney  tube  draws  the  flame 
to  a  definite  form  and  hides  the  top  of  it  from  view. 

"A  mica  window  in  the  tube  allows  the  tip  of  the  flame  to  be  seen 
and  the  height  to  be  regulated,  so  that  the  tip  is  somewhere  between 
the  bottom  of  the  window  and  a  crossbar.  A  tube  290  mm.  long, 


STANDARDS    AND   BURNERS  37 

and  50  mm.  inner  and  52  mm.  outer  diameter,  surrounds  the  chim- 
ney tube  and  draws  in  air  at  its  base. 

"The  chimney  tube  projects  65  mm.  below  and  76  mm.  above  this 
outer  tube.  The  heated  air  passes  from  the  top  of  the  outer  tube 
to  another  tube  529^  mm.  long,  and  of  23  mm.  inside  and  25  mm. 
outside  diameter,  which  is  placed  parallel  to  the  first  tube,  and  with 
its  axis  67  mm.  distant  from  the  axis  of  the  latter.  From  the  bot- 
tom of  this  tube  the  air  passes  to  the  center  of  the  steatite  ring  of  the 
burner.  The  outer  diameter  of  this  ring  is  24  mm.,  the  inner  diam- 
eter 14  mm.,  and  there  are  30  holes,  each  one  1.25  mm.  in  diameter. 

"A  conical  shade  102  mm.  wide  at  the  base,  55  mm.  wide  at  top, 
and  57  mm.  high,  having  an  opening  34  mm.  wide,  is  placed  around 
the  flame.  The  light  which  serves  as  the  zo-candle  standard  passes 
through  the  opening  in  this  shade.  Leveling  screws  are  provided 
by  which  the  lamp  is  adjusted  until  it  is  vertical,  and  the  height  of 
the  steatite  ring  (when  using  the  table  photometer)  is  353  mm.  from 
the  table." 

The  Pentane  lamp  made  in  the  United  States  differs  from  the 
above  only  in  minor  details,  the  most  important  being  that  the 
saturator  is  connected  with  the  burner  by  brass  tubing,  which  would 
seem  to  be  a  distinct  improvement  over  the  rubber  hose  employed 
with  the  English  model.  The  total  weight  of  the  apparatus  is 
25  pounds,  and  the  price  $75. 

The  fuel  used  consists  principally  of  a  hydrocarbon,  pentane, 
(C5H12),  belonging  to  the  same  series  as  methane  and  ethane,  and 
obtained  by  the  distillation  of  gasoline.  From  the  nature  of  its 
origin  it  will  be  readily  seen  that  it  cannot  be  made  (at  least  com- 
mercially) absolutely  pure,  but  always  contains  small  quantities  of 
other  hydrocarbons.  Since  the  presence  of  these  latter  in  any  con- 
siderable amount  will  seriously  affect  the  value  of  the  standard,  it 
is  necessary  that  every  fresh  batch  of  pentane  should  be  prepared 
and  tested  by  a  chemist,  and  for  this  reason,  among  others,  the 
standard  is  not  as  available  for  the  smaller  companies.  (An  illus- 
tration of  the  lamp  is  seen  in  Fig.  9. ) 

The  accuracy  of  the  lamp  is  unquestionable,  and  at  the  present 
time  it  is  the  most  highly  esteemed  standard  in  the  United  States, 


GAS   AND    GAS   METERS 


The  author  does  not  believe,  however,  that  the  last  word  has  been 
spoken  on  this  question,  for  there  are  several  imperfections  and 

disadvantages  still  to  be  overcome. 
First,  the  lamp  is  too  expensive,  and 
the  cost  of  its  fuel  ($3  per  gallon)  too 
great.  Second,  the  fuel  is  inflammable 
and  greatly  increases  insurance  risk  and 
difficulty  of  transportation.  Third, 
the  pentane  employed  must  be  care- 
fully tested  by  a  chemist,  and  this 
requires  special  facilities.  Fourth,  it 
is  believed  that  the  simplicity  and  ease 
of  operation  could  be  somewhat  in- 
creased, if  we  remember  that  these 
standards  are  being  considered  purely 
_G  from  the  standpoint  of  the  practical 
B  man,  and  not  at  all  in  the  line  of 
theoretical  or  primary  standards. 

Before  concluding  this  subject  a  word 
should  be  said  regarding  electric  stand- 
ards. The  convenience  of  these  in 
certain  places,  and  their  accuracy  are 
unquestioned,  but  they  are  unsuited  for 
use  in  the  photometry  of  gas  flames, 
because  the  electric  lamp  is  entirely 
unaffected  by  atmospheric  conditions. 
Mr.  Gartley  says:  "To  compare  a 
gas  flame  against  an  electric  lamp, 

normal  atmospheric  conditions  are  imperative,  otherwise  an  error 
of  as  much  as  10  per  cent  may  be  introduced,  generally  against  the 
gas  flame."  1 

Burners.  The  burner  question  has,  like  that  of  standards,  had  a 
long  and  interesting  history,  and  were  there  time  it  would  be  profit- 
able to  trace  the  evolution  of  the  burner  from  its  remote  ancestor, 
the  lava  tip,  down  to  its  present  magnificence  in  the  form  of  the 

1  Proceedings  of  American  Gas  Institute,  October,  1907. 


Fig.  9.     Pentane  Lamp. 


STANDARDS   AND   BURNERS  39 

Metropolitan  No.  2,  or  Carpenter  burner.  Without  going  into  this 
in  detail,  however,  it  suffices  to  say  that  one  fact  stands  out  clearly : 
the  end  and  aim  of  all  the  research  along  this  line  has  been  to  pro- 
duce a  burner  which  should  do  justice  to  the  actual  candlepower  of 
the  gas;  and  up  to  recent  years  no  burner  has  been  found  which 
could  accomplish  this,  principally  because  no  device  had  been  dis- 
covered which  properly  regulated  the  air  supply  according  to  the 
quality  of  the  gas. 

Hornby,  in  his  Gas  Manufacture,  says:  "In  batswing  or  fishtail 
burners  the  size  and  angle  of  the  apertures  determine  the  amount  of 
air,  while  in  the  Argand,  the  chief  regulating  agency  is  the  chimney 
by  which  the  amount  of  air  admitted  is  under  perfect  control.  With 
a  poor  gas  little  air  is  needed,  and  the  best  burners  for  such  a  gas 
are  those  with  large  holes.  Here  the  directive  force  with  which  the 
gas  issues  is  small  in  proportion  to  the  quantity  passing,  and  so  the 
supply  of  air  is  likewise  correspondingly  small.  The  reverse  is 
true  for  rich  gases." 

While  it  is  somewhat  difficult  to  admit  that  the  air  supply  is 
perfectly  controlled  by  the  chimney,  it  is  true  that  the  latter  serves 
a  twofold  purpose  of  shielding  the  flame  from  drafts  and  of  draw- 
ing upon  its  surface  the  air  needed  for  combustion.  With  flat- 
flame  burners  the  proper  air  supply  is  secured  by  the  pressure  at 
which  the  gas  issues  from  the  burner  forcing  the  white-hot  carbon 
particles  into  intimate  and  rapid  contact  with  the  air. 

The  only  burner,  however,  which  accurately  controls  the  air 
supply  is  the  Metropolitan  No.  2,  or  Carpenter  burner,  which  in 
its  essential  features  is  an  Argand  burner  fitted  with  an  air  shutter 
for  regulating  the  amount  of  air  admitted  to  the  interior  of  the 
flame.  Because  of  this  regulator  the  burner  gives  with  low  candle 
gas  a  higher  result  than  any  other. 

And  now  the  question  immediately  arises,  Why  should  not  this 
burner  be  employed  in  every  case,  at  least  for  coal  gas?  The 
answer  to  this  will  be  found  in  the  consideration  of  two  or  three 
facts.  In  Massachusetts  the  law  requires  that  the  gas  shall  be 
tested  with  the  burner  best  adapted  to  it,  which  is  at  the  same  time 
practical  for  use  by  the  consumer,  and  the  authorities  in  that  state 


GAS   AND    GAS   METERS 


.122— »     *- 


Fig.  10.     Metropolitan  No.  2,  or  Carpenter  Burner. 


STANDARDS   AND   BURNERS  41 

have  interpreted  this  to  mean  a  burner  which  is  not  only  satisfactory 
in  its  mechanical  details,  but  which  in  cost  is  within  the  reach 
of  everyone.  The  price  of  the  Metropolitan  No.  2  is  $25,  and 
this  would  seem  to  place  it  beyond  the  reach  of  most  consumers. 
In  London  a  similar  regulation  is  in  force,  but  is  interpreted 
differently. 

Again,  in  certain  localities  the  choice  of  a  burner  must  be 
governed  by  local  considerations;  thus,  in  New  York,  the  Second- 
Class  Cities  Law  specifically  calls  for  the  use  of  the  Suggs  New  F 
and  Old  D  Argand  burners  and  of  the  No.  7  Slit  Union  Bray  burner, 
dependent  upon  the  nature  of  the  gas  to  be  tested;  and  the  order 
of  the  former  Commission  of  Gas  and  Electricity  of  that  state, 
which  has  thus  far  been  continued  by  the  Public  Service  Commis- 
sion of  the  Second  District,  requires  the  use  of  the  above  burners 
in  all  cities  and  towns  under  its  jurisdiction  where  coal  or  water 
gas  is  made. 

Now,  without  defending  the  \^sdom  of  these  regulations,  it 
would  seem  advisable  for  gas  companies  to  conform  to  local  laws 
and  customs  in  the  manner  of  testing  their  gas  in  order  that  they 
may  the  more  carefully  comply  with  the  regulations  laid  down 
for  their  control. 

In  cases  where  the  above  conditions  do  not  apply,  the  use  of  the 
Carpenter  burner  is  to  be  recommended  for  coal  gas,  and  the  No.  7 
Slit  Union  Bray  burner  for  water  gas.  In  the  appendix  will  be 
found  a  table  compiled  from  data  secured  by  the  author  and  his 
assistants  which  will  illustrate  the  results  to  be  expected  with  the 
two  Argand  and  the  Bray  burners.  These  tests  were  obtained  in 
the  course  of  routine  work  in  a  large  number  of  places  throughout 
the  state  of  New  York,  and  no  two  are  from  the  same  sample  of 
gas.  These  figures  will  serve  to  show  that  no  hard  and  fast  rule 
can  be  laid  down  regarding  the  proper  burner  to  be  used  in 
individual  cases,  and  that  the  photometrist  who  honestly  seeks  for 
the  correct  result  will  try  more  than  one  burner  in  all  cases  of 
reasonable  doubt. 

In  the  instances  cited  above,  Argands  of  the  types  known  as 
New  Style  F  and  Old  Style  D  are  to  be  employed.  The  Old  D 


42  GAS   AND    GAS   METERS 

which  is  furnished  with  photometers  is  not  a  standard  burner,  and 
tests  by  the  writer  and  others  have  shown  that  it  is  not  to  be 
recommended.  The  standard  Old  D  burner  will  as  a  general 
thing  give  the  better  result  with  a  gas  of  less  than  16  candlepower, 
and  the  New  F  is  almost  invariably  the  better  burner  for  candle- 
powers  between  17  and  20.  The  rules  issued  by  the  New  York 
Public  Service  Commission  of  the  Second  District  cover  this  point 
well,  and  are  in  substance  the  same  as  the  above. 

The  writer  wishes  to  be  very  distinctly  understood  with  regard 
to  this  matter  of  burners.  The  Carpenter  burner  comes  nearer 
to  bringing  out  the  actual  candlepower  of  a  coal  gas  than  does  any 
other  burner;  it  is  therefore  unquestionably,  from  a  scientific  or 
theoretical  standpoint,  to  be  recommended  for  adoption.  It  is 
only  on  the  grounds  of  expediency  and  in  deference  to  local  condi- 
tions that  other  burners  are  recommended  for  special  cases. 

For  a  straight  oil  gas  a  3-foot  steel  tip  burner  may  be  used;  and 
for  acetylene,  a  Perfection  No.  3,  which  is  made  especially  for  this 
gas.  Gasolene  gas  is  tested  with  a  Tirfill,  and  for  oil-air  gas  either 
a  Suggs  Table  Top  tip  or  an  F  Argand  may  be  used. 

As  a  rule,  a  chimney  7  inches  by  if  inches  should  be  used, 
although  in  the  case  of  certain  low  candlepower  gases  a  6-inch 
chimney  will  be  found  to  give  better  results  simply  because  it  more 
nearly  adjusts  the  air  supply  to  the  quality  of  the  gas. 

The  New  F  and  Old  D  Argand  burners  cost  at  the  time  of 
writing  $5.50  apiece,  and  are  made  to  order  in  England.  The 
Bray  burner  costs  about  25  cents,  and  may  be  procured  of  nearly 
any  of  the  large  dealers  of  gas  appliances.  The  chimneys  are 
$3.00  a  dozen,  and  as  a  rule  can  be  obtained  only  in  the  larger 
cities. 


CHAPTER  III. 
CANDLEPOWER  TESTS  WITH  COAL  AND  WATER  GAS. 

BEFORE  commencing  the  actual  operations  for  taking  the 
candlepower,  there  are  two  very  important  points  to  be  attended 
to.  First,  the  photometer  bar  must  be  measured;  second,  the 
meter  must  be  tested.  With  regard  to  the  latter,  little  need  be 
said  here,  as  the  subject  will  be  fully  treated  in  the  chapter  on 
meter  testing.  We  shall,  therefore,  assume  that  the  gauge  glass  of 
the  meter  bears  a  mark  at  which  the  lowest  edge  of  the  meniscus 
must  rest  if  the  meter  is  to  register  correctly. 

The  measurement  of  the  photometer  is  most  essential  and  must 
be  done  with  extreme  care,  since  on  the  accuracy  of  this  depends 
the  correctness  of  all  future  work.  A  method  of  procedure  is 
here  suggested  which  is  simple  and  yet  sufficiently  accurate  if 
carefully  followed  out.  Let  us  assume  the  bar  to  be  of  the  60- 
inch  type.  Then  the  distance  between  the  plumb  bobs,  defining 
the  position  of  gas  and  standard,  is  to  be  just  60  inches.  If  this 
proves  to  be  incorrect,  it  can  be  rectified  by  moving  the  bob  at 
one  end,  but  the  question  of  which  bob  to  adjust  must  await  its 
answer  until  further  measurements  have  been  taken.  Now  drop 
a  plumb  line  from  the  i6-candle  mark  on  the  scale  to  the  pho- 
tometer table.  As  the  point  thus  found  will  lie  somewhat  in  the 
rear  of  the  line  connecting  the  two  plumb  bobs,  it  is  necessary  to 
use  draftsman's  triangles  or  some  similar  device  for  drawing  a 
line,  through  the  point  and  perpendicular  to  the  axis  of  the  pho- 
tometer. Next  measure  the  distance  of  this  point  (in  a  straight 
line  parallel  to  the  photometer  bar)  from  the  bob  at  the  gas  or 
standard  end. 

If  the  bar  was  calibrated  for  use  with  a  one-candle  standard, 
the  square  of  the  distance  to  the  gas  divided  by  the  square  of  the 
distance  to  the  standard  should  equal  16,  and  consequently  with 

43 


44  GAS  AND    GAS   METERS 

the  60- inch  bar  the  standard  will  be  12  inches  and  the  gas  48 
inches  from  the  i6-candle  mark.  In  a  similar  manner  the 
observer  may  check  as  many  of  the  marks  as  may  seem 
desirable. 

If  the  bar  was  graduated  with  a  view  to  reading  the  candle- 
power  direct  with  a  2-candle  standard,  as  is  often  the  case,  it  is 
evident  that  the  i6-candle  mark  will  stand  where  the  8-candle 
mark  would  be  were  the  standard  of  only  one-candle  value.  In 
case  the  location  of  the  point  is  incorrect,  move  either  the  gas  or 
standard  until  the  error  is  rectified. 

For  example,  on  a  6o-inch  bar  the  i6-candlepower  mark  is 
found  to  be  nj  inches  from  the  standard  and  48  inches  from  the 
gas.  This,  of  course,  means  that  the  bar  is  too  short,  and  the 
standard  bob  should  be  set  one-half  inch  farther  away  from  the  gas 
end.  It  frequently  happens,  especially  with  closed-bar  photom- 
eters, that  the  wood  used  in  their  construction  was  not  perfectly 
seasoned,  or  else  the  photometer  may  have  been  set  up  in  a 
locality  where  the  conditions  of  temperature,  moisture,  etc.,  may 
have  caused  it  to  expand  or  shrink.  It  is,  therefore,  advisable  to 
remeasure  the  bar  occasionally;  and  if  the  marks  of  the  original 
measurement  have  been  preserved  on  the  photometer  table  this 
may  be  done  with  great  ease  and  rapidity. 

In  some  instances  it  may  be  found  that  the  total  length  of  the 
bar  is  correct,  but  that  the  position  of  the  marks  on  the  scale  is 
in  error;  in  such  cases  it  will  be  necessary  to  move  the  scale 
itself.  Another  method  of  measuring  is  to  determine  the  position 
of  one  mark  on  the  scale  with  extreme  accuracy,  and  then  measure 
the  distances,  on  the  scale  itself,  of  the  other  marks  from  this. 

A  formula  for  calculating  the  proper  position  of  any  mark  on 
the  scale  has  been  worked  out  by  the  author,  and  as  he  has  never 
seen  it  in  this  form  in  print,  it  is  thought  to  be  worthy  of  insertion 
here. 

(Px2  -  x2}  +  2  Lx  =  L2 

where  oc  =  distance  from  the  standard  to  the  desired  mark, 
L  =  the  total  length  of  the  bar, 
P  =  the  point  chosen  (as  lo-candlepower  mark). 


CANDLEPOWER  TESTS  45 

To  illustrate,  suppose  it  is  desired  to  know  the  location  of  the 
lo-candle  mark  on  a  6o-inch  bar,  then 

(lO  X2  —  X2)  +   120  X  =  3600. 

Solving  this  we  find  x  =  14.41,  so  the  zo-candle  mark  should  be 
14.41  inches  from  the  standard  where  the  value  of  the  latter  is 
one  candle. 

Preparations  for  the  Test.  It  is  always  well  to  spend  a  few  min- 
utes in  looking  over  the  apparatus  to  see  that  everything  is  in  proper 
order.  If  a  closed-bar  photometer  is  used,  see  that  it  is  level,  and 
that  the  interior  of  the  bar  is  free  from  dust  and  contains  no  obstruc- 
tion to  the  passage  of  light  to  the  disc.  The  precaution  against 
dust  is  necessary  because  while  the  dead  black  of  the  bar  when 
clean  affords  but  small  chance  for  reflection,  a  layer  of  dust  on  the 
bottom  of  the  gallery,  which  is  only  slightly  lower  than  the  disc, 
makes  a  most  excellent  reflecting  surface. 

It  may  seem  an  absurdity  to  have  added  a  warning  against 
obstructions  in  the  bar,  but  on  several  occasions  the  writer  has 
found  that  company  employees  have  considered  the  bar  a  most 
desirable  substitute  for  a  closet,  and  bottles,  Welsbach  mantles, 
chimneys,  and  other  things  have  had  to  be  removed  before  a  test 
could  be  made. 

The  ventilation  holes  in  the  bottom  of  the  gas  and  candle  cham- 
bers must  be  clear,  and  nothing  should  be  placed  over  these  to 
obstruct  the  free  passage  of  air. 

The  mirrors  and  sight  box  must  be  kept  clean  and  especial  care 
exercised  to  see  that  a  coating  of  dust  has  not  settled  on  the  disc. 
A  recent  experience  of  the  writer's  well  illustrates  the  latter  point. 
A  disc  which  had  been  in  use  by  one  of  his  assistants  for  several 
months,  with  perfectly  satisfactory  results,  suddenly  changed  so 
that  the  readings  from  its  two  sides  differed  from  each  other  by  as 
much  as  3  candlepower,  and  there  seemed  to  be  no  reasonable 
explanation  of  the  phenomenon,  save  that  dust  had  collected  on  one 
or  both  of  the  surfaces.  Moreover,  not  only  does  cleanliness  pro- 
mote accuracy,  but  it  greatly  eases  the  strain  on  the  operator,  as 
anyone  who  has  tried  to  read  a  poor  disc  reflected  in  dirty  mirrors 


46  GAS   AND   GAS    METERS 

can  affirm.  It  occasionally  happens,  and  more  especially  with, 
portable  photometers,  that  the  disc  becomes  perforated;  this  ren- 
ders it  unfit  for  use,  and  a  new  one  should  be  immediately 
substituted. 

See  that  the  burner  is  free  from  dirt,  and  has  not  been  chipped  or 
otherwise  injured,  and  that,  in  the  case  of  the  Argand,  it  is  provided 
with  a  clean  and  perfectly  dry  chimney.  Test  the  governor  and 
pressure  gauge  to  see  that  they  are  working  freely.  Ascertain  that 
the  meter  is  level  and  is  not  subject  to  any  strain  due  to  improper 
height  of  the  pipes  leading  to  the  inlet  or  outlet.  The  water  in 
the  meter  should  be  changed  occasionally,  and  for  this  reason  both 
the  funnel  and  the  outlet  water  cock  should  be  easily  accessible. 
Whenever  this  change  is  made  the  fresh  water  must  be  thoroughly 
saturated  with  gas  before  the  meter  can  be  used.  Such  saturation 
is  best  accomplished  by  burning  gas  through  the  meter  for  at  least 
one  hour. 

The  candle  balance  should  be  examined  with  great  care,  as  this 
offers  one  of  the  most  fruitful  sources  of  error.  Rust,  sperm  and 
dirt  are  continually  collecting  on  knife  edges  and  bearings,  and  the 
fact  that  the  balance  was  cleaned  yesterday  offers  no  assurance  that 
it  will  work  properly  to-day.  It  is  always  a  source  of  surprise  to 
those  unaccustomed  to  the  use  of  a  balance  to  note  how  wide  a 
variation  in  results  may  be  caused  by  a  seemingly  infinitesimal  par- 
ticle of  sperm.  If  we  remember,  however,  that  the  whole  success 
of  the  balance  depends  on  the  practical  absence  of  friction,  and  on 
the  bearing  surfaces  being  as  thin  as  possible,  the  matter  does  not 
seem  at  all  strange. 

The  moisture  and  oxygen  in  the  atmosphere  are  continually 
attacking  the  steel  of  the  knife  edges  and  forming  small  particles  of 
rust  which,  coming  between  the  knife  edge  and  bearing,  act  as  a 
brake  on  the  action  of  the  balance.  Spatterings  of  sperm  from  the 
candles  also  fall  on  the  bearings  and  attract  and  hold  dust,  and  this 
causes  the  balance  to  swing  more  slowly  than  it  should  and  give 
totally  incorrect  weights.  Unless  the  working  parts  of  the  balance 
be  clean,  and  the  knife  edges  sharp  and  smooth,  it  will  matter  little 
how  fine  a  disc,  burner  and  meter  one  has,  or  how  accurately  one 


CANDLEPOWER   TESTS  47 

can  read;  the  results  will  be  utterly  inaccurate.  Never,  therefore, 
start  to  make  a  candlepower  test  without  first  cleaning  every  knife 
edge  and  bearing  on  the  balance. 

This,  of  course,  applies  only  to  that  type  of  balance  where  the 
bearings  are  exposed;  in  other  forms,  such  as  the  Becker,  the  above 
precautions  are  largely  unnecessary,  but  to  compensate  for  this  the 
balance  must  be  adjusted  before  every  test,  and  the  beam  carefully 
dusted.  It  is  an  excellent  plan  to  keep  a  small  box  of  the  size  of  a 
cigar  box  near  the  balance  and  to  place  all  waste  sperm,  candles, 
matches  and  cleanings  of  the  balance  in  this. 

The  10  or  20-grain  weight  to  be  used  should  have  been  stand- 
ardized on  some  delicate  analytical  balance,  and  must  be  inces- 
santly watched,  as  it  is  extremely  easy  for  a  slight  film  of  sperm  to 
gather  in  spots  or  in  the  grooves  formed  by  the  lines  of  the  numbers 
with  which  it  is  stamped.  Always  clean  the  weight  before  each 
test,  but  in  doing  so,  use  only  a  soft  rag,  as  any  harsher  substance 
will  readily  remove  fine  metallic  particles  and  thus  destroy  its 
accuracy. 

Having  now  made  the  general  preparations,  the  first  step  in 
specific  tests  is  to  clear  the  stale  gas  from  the  service,  and  be  certain 
that  the  supply  is  fresh  from  the  main.  If  a  blow-off  has  been 
provided  this  may  be  accomplished  in  from  5  to  10  minutes,  and 
this  is  the  most  satisfactory  method  of  procedure.  If  there  is  no 
blow-off  the  pipes  may  be  cleared  by  burning  the  gas  for  a  period 
of  time  dependent  on  the  size  and  length  of  the  service.  In  almost 
every  case  from  20  minutes  to  half  an  hour  will  be  sufficient,  but 
it  is  to  be  remembered  that  during  this  time  the  air  in  the  pho- 
tometer room  is  being  heated  and  fouled  by  the  products  of  com- 
bustion, and  this  is  one  reason  for  the  desirability  of  installing  a 
blow-off. 

The  next  point  to  be  considered  is  the  meter.  The  accuracy  of 
this  depends  upon  the  degree  of  care  with  which  the  water  level  is 
adjusted,  and,  remembering  this  fact,  it  is  astounding  to  see  the 
number  of  companies  where  this  detail  is  practically  ignored.  The 
writer  has  met  man  after  man  who  has  argued  with  him  regarding 
the  terrible  errors  of  candles  and  who  would  not  use  a  closed-bar 


48  GAS   AND    GAS   METERS 

photometer  because  of  its  supposed  inaccuracy,  and  yet  whose 
meter  was  in  error  from  i  to  10  per  cent,  because  of  neglect  to 
adjust  the  water  line. 

It  is  estimated  that  with  a  6-foot  wet  meter  a  difference  of  one- 
sixteenth  of  an  inch  in  the  water  level  makes  a  difference  of  about 
i  per  cent;  thus,  it  will  be  readily  admitted  that  the  level  should  be 
corrected  before  every  test,  since  the  gas  in  passing  picks  up  some 
of  the  water,  and  since  a  change  in  temperature  will  seriously  affect 
the  water  volume. 

The  meter  is  generally  standardized  to  be  correct  when  the 
lowest  edge  of  the  meniscus  just  touches  the  scratch  or  other  cali- 
bration mark  on  the  gauge  glass  when  there  is  no  pressure  whatso- 
ever on  the  meter.  Hence,  to  adjust  the  latter,  while  connected  to 
the  photometer,  it  is  necessary  that  both  inlet  and  outlet  be  opened 
to  the  air.  This  is  accomplished  by  removing  the  plug  from  the 
dry  well  at  the  back  of  the  meter  and  opening  the  burner  cock  of 
the  photometer,  the  gas  being  shut  off  from  the  meter. 

Before  proceeding  with  the  operation  it  is  customary  at  this 
point  to  ascertain  whether  any  water  has  collected  in  the  dry  well, 
and  if  so,  to  expel  it.  This  may  be  done  by  placing  one  finger 
over  the  outlet  to  the  dry  well  and  turning  the  gas  partly  on.  By 
removing  and  replacing  the  finger  the  operator  can  tell  by  the 
sound  whether  water  be  present,  and  if  it  is  found,  can  blow  it 
out  by  means  of  the  gas  pressure.  This  test  serves  also  to  show 
whether  the  meter  is  working  properly,  since  if  there  is  a  stoppage 
when  the  finger  is  placed  over  the  dry  well  and  the  gas  turned  on 
(the  burner  cock  being  closed  for  this  test),  the  water  in  the  gauge 
will  not  move  freely  as  it  should  do. 

Now  the  water  level  is  examined,  and  if  the  lowest  edge  of  the 
meniscus  does  not  just  touch  the  standard  mark  on  the  gauge, 
water  is  added  through  the  funnel  or  removed  by  the  outlet  cock 
until  the  proper  level  is  attained.  It  will  often  be  found  well  to 
hold  a  sheet  of  white  paper  or  a  lighted  match  behind  the  gauge 
glass  in  order  to  facilitate  the  reading  of  the  meniscus.  When  the 
water  level  is  correct,  close  the  funnel  valve  and  replace  the  plug 
in  the  dry  well.  Test  for  a  leak  by  turning  on  the  gas,  closing  the 


CANDLEPOWER   TESTS  49 

burner  orifice  with  the  finger,  or,  better,  with  a  rubber  cap  closed 
at  one  end,  and  then  watching  the  hand  of  the  meter.  If  this 
does  not  move,  the  meter  and  connections  are  tight,  and  the  gas 
may  now  be  lighted  in  the  test  burner. 

If  a  blow-off  has  been  employed,  it  will  be  but  5  or  10  minutes 
before  the  gas  itself  is  ready  for  a  test,  but  the  latter  must  not  be 
commenced  immediately  for  several  reasons.  In  the  first  place, 
whatever  water  has  been  added  to  the  meter  must  be  saturated 
with  gas.  Second,  the  meter  and  pipes  leading  from  it  to  the 
burner  must  be  cleaned  of  stale  gas.  Third,  time  must  be  allowed 
for  equalization  of  temperatures  between  the  water  in  the  meter 
and  the  incoming  gas. 

While  waiting  for  these  things  to  be  accomplished,  the  observer 
should  see  that  the  burner  is  accurately  aligned  and  should  regu- 
late the  flow  of  the  gas.  The  rate  is  supposed  to  be  5  feet  per 
hour,  but  only  under  standard  conditions,  namely,  60°  F.  and 
760  mm.  or  30  inches  pressure.  When  such  conditions  do  not 
prevail,  it  is  necessary  to  calculate  what  rate  under  the  existing 
circumstances  would  be  equivalent  to  5  feet  per  hour  under 
standard  conditions.  For  this  calculation  the  writer  always 
employs  a  method  derived  from  Mr.  Jenkins,  the  State  Inspector 
of  Massachusetts,  which  will  be  explained  in  detail  in  the  para- 
graph on  candlepower  corrections.  In  brief,  i  per  cent  is  added 
for  every  4  degrees  over  60  degrees,  and  i  per  cent  for  every 
three-tenths  of  an  inch  under  30  inches.  Thus,  if  the  tem- 
perature in  the  meter  is  68  degrees  and  the  barometer  stands  at 
30.15,  the  correction  would  be  made  as  follows: 

(68  —  60) H-  4=2  per  cent  + 
(30.15  -  30.00)-=-  0.3  =  0.5  per  cent  - 

Combining  these,  2  per  cent  —  0.5  per  cent=  1.5  per  cent  + 
5.0  feet  -r-  0.985  (or  i.oo  —  .015)=  5.08. 

Consequently,  under  the  assumed  conditions,  the  meter  must 
register  5.08  feet  per  hour  in  order  to  be  actually  passing  5  feet 
measured  under  standard  conditions.  If  the  meter  dial  is  divided 


SO  GAS   AND   GAS   METERS 


into  one  hundred  spaces  of  y^^  foot  each,  in  order  to  be  passing 
5.08  feet  per  hour,  the  large  hand  must  pass  over  84.7  divisions 
per  minute,  or  0.0847  f°ot  (that  is,  5.08  -r-  60).  If  the  divisions 
are  T^Vo  foot,  the  hand  must  pass  over  101.6  marks  or 
0.0847  "^TsW  All  of  this  calculation  may  be  easily  carried  out 
in  the  head  with  sufficient  accuracy;  the  only  difficult  part,  the 
division  of  5  feet  by  985,  may  be  obviated  by  multiplying  the 
5  feet  by  1.5  per  cent  and  adding  the  product  to  the  5  feet.  It  is 
necessary  to  perform  this  rating  with  considerable  care,  since  it  is 
usually  done  by  one-minute  observations,  and  any  error  at  this 
point  will  be  magnified  tenfold  when  the  regular  test  is  made. 

The  next  point  is  to  regulate  the  outlet  governor  so  that  the 
pressure  at  the  burner  shall  be  i  inch.  Many  photometers  are 
not  equipped  with  governors  and  consequently  the  gas  is  tested 
at  the  street  pressure.  There  are  two  important  objections  to 
such  a  course  of  procedure.  First,  the  fact  that  the  pressure  in 
the  mains  is  seldom  absolutely  uniform,  and  second,  that  experi- 
ments have  shown  that  the  candlepower  varies  with  the  pressure 
to  a  certain  extent. 

The  writer  made  a  number  of  tests  of  burners  under  varying 
conditions  of  pressure  and  rate,  and  a  few  of  these  will  be  found  in 
a  table  in  the  appendix.  From  the  figures  there  given  it  will  be 
evident  that  it  is  necessary  to  prescribe  a  pressure  that  shall  not 
only  make  for  uniformity,  but  shall  also  give  the  highest  efficiency 
with  the  burner  employed. 

While  the  gas  is  being  cleared  from  the  pipes,  the  candles  should 
be  lighted,  as  these  must  burn  from  15  to  20  minutes  before  being 
ready  for  the  test.  The  candles  to  be  used  are  what  are  known 
as  sixes,  that  is,  weighing  six  to  the  pound.  There  is  a  form  on 
the  market  which  is  half  the  size  of  the  above  and  known  as  twelves, 
but  these  are  not  to  be  recommended,  since  in  a  number  of 
instances  they  have  been  shown  to  vary  considerably  from  the 
sixes  which  are  the  official  candles  and  hence  used  in  nearly  all  the 
state  and  municipal  inspections. 

Assuming  then  that  sixes  are  to  be  used,  if  the  candle  to  be 
employed  be  a  fresh  one,  it  must  first  be  cut  in  two.  The  general 


CANDLEPOWER  TESTS  5 1 

method  of  effecting  this  is  to  roll  the  candle  on  a  table  under  a 
knife  blade  until  cut  through.  Then  the  operator  has  the  choice 
of  two  ways  of  proceeding.  First,  he  can  burn  the  candle  from  the 
middle  towards  the  ends,  or,  second,  he  can  burn  only  the  lower 
half  in  that  manner  and  the  upper  half  from  the  end  towards  the 
middle.  The  first  method  is  recommended  by  many  writers 
because  of  the  fact  that  the  candle  increases  slightly  in  size  from 
the  upper  to  the  lower  end,  and  by  burning  from  the  middle 
towards  the  ends,  one-half  of  the  candle  is  decreasing  in  diameter 
as  the  consumption  progresses,  while  the  other  half  is  increasing. 
This  is  supposed  to  render  the  light  more  uniform  throughout  the 
life  of  the  candle. 

On  the  other  hand,  Mr.  Hartley  of  England,  after  careful 
investigation,  is  satisfied  that  this  advantage  is  more  theoretical 
than  real.  There  are  two  points  in  favor  of  the  second  method: 
one  is,  that  by  a  certain  procedure  in  preparation  a  saving  of 
about  10  per  cent  can  be  secured  in  the  expense  for  candles;  and 
the  other  reason  will  appear  more  clearly  in  what  follows,  but  is 
along  the  line  of  economy  and  a  better  condition  of  the  wick. 

If  the  candle  is  to  be  burned  by  the  second  method,  the  above 
economy  is  secured  by  the  following  procedure:  Do  not  cut  the 
candle  in  the  center,  but  at  that  point  insert  a  fine,  sharp  blade, 
making  as  small  a  hole  as  possible,  and  cut  the  wick  (Fig.  n). 
Then,  about  an  inch  below  the  incision  cut  carefully  around  the 
entire  candle  nearly  into  the  wick,  taking  pains,  however,  not  to 
damage  the  latter. 

Now  by  taking  one-half  of  the  candle  in  either  hand,  a  slow, 
steady,  straight  pull  will  separate  the  two  halves,  leaving  the  wick 
of  the  lower  part  ready  to  light.  By  this  means  the  inch  of  sperm, 
which  is  usually  pared  or  burned  off,  is  left  at  the  bottom  of  the 
upper  half,  and  while  this  portion  is  wickless,  that  fact  is  of  no 
consequence,  since  it  is  never  possible  to  consume  the  last  inch  or 
two  in  any  case. 

If  the  candle  is  entirely  severed  in  the  middle  a  portion  of  sperm 
about  one  inch  from  the  end  to  be  lighted  must  be  removed,  and 
this  may  be  done  either  by  paring  the  end  to  a  conical  shape  and 


52  GAS   AND    GAS    METERS 

burning  off  the  sperm,  or  by  cutting  in  nearly  to  the  wick,  as 
described  above,  and  pulling  off  the  piece  thus  severed,  leaving 
the  projecting  wick  intact. 

The  former  procedure  is  recommended  by  the  American  Gas 
Institute  and  has  the  advantage  that  there  is  no  liability  of  injur- 
ing the  wick.  The  latter  method  is  used  by  the  state  inspectors 
in  Massachusetts  and  New  York,  and  prepares  the  candle  more 
quickly  for  use,  while  with  a  little  practice  and  due  care  there  is 
no  danger  of  spoiling  the  wick.  The  upper  end  of  the  candle 
may  be  burned  off  or  the  sperm  surrounding  the  wick  may  be 
cut  away,  but  cannot  be  pulled  off  as  with  the  lower  half. 


Fig.  ii.     Method  of  Cutting  Candles. 

It  is  the  writer's  practice  to  cut  off  a  small  portion  of  this  end 
of  the  wick  with  a  sharp  knife,  as  it  is  nearly  always  frayed  and 
does  not  give  a  clear-cut  glowing  end. 

The  halves  being  in  the  condition  shown  in  Fig.  12,  are  now 
ready  for  use.  Bring  the  flame  of  the  match  in  contact  with  the 
end  of  the  wick,  and  when  the  latter  is  ignited,  invert  the  candle 
over  the  waste  box,  holding  it  at  a  slight  angle  to  the  perpendic- 
ular. Revolve  slowly  in  the  ringers  until  the  sperm  at  the  base 
of  the  wick  melts  and  drops  off  and  a  cup-shaped  depression  is 
formed.  Then  reinvert  and  insert  in  the  candle  holder.  After  a 
short  period  the  wick  will  begin  to  curve  at  the  end,  and  the  point 
thereof  to  glow. 

The  glowing  end  of  one  wick  should  point  towards  the  disc 
and  that  of  the  other  towards  the  observer;  thus  the  two  wicks 


CANDLEPOWER  TESTS  53 

form  a  right  angle  with  each  other.  The  reason  for  this  posi- 
tion is  simple;  if  both  ends  pointed  towards  the  disc,  the 
smaller  areas  of  the  flames  would  be  towards  the  latter  and  the 
results  would  be  too  favorable  to  the  gas;  while  if  both  wicks 
were  parallel  to  the  disc,  the  converse  would  be  true. 

In  lighting  candles  which  are  in  the  holder  and  which  have 
already  been  used,  it  is  only  necessary  to  apply  a  flame  to  the 
wick,  and  as  soon  as  it  is  ignited,  place  a  drop  of  sperm  in  the  cup 
at  the  base.  This  latter  precaution  is  observed  because  when 
first  lighted  the  sperm  of  the  candle  is  hard  and  does  not  soften 
immediately,  and  so  the  wick  has  difficulty  in  drawing  up  the 
fuel  necessary  for  combustion.  The  drop  placed  in  the  cup 
relieves  this  strain  until  such  time  as  the  sperm  around  the  wick 
shall  have  become  softened.  In  no  case  touch  the  wick  with  any 
hard  object,  or  it  is  extremely  liable  to  be  injured. 

When  burning  properly  the  wick  should  curve  at  nearly  a 
right  angle  to  the  length  of  the  candle,  and  the  end  should  be 
small  and  glow  with  a  clean  red  heat.  The  cup  at  the  base  of  the 
wick  should  extend  the  full  diameter  of  the  candle  and  should  be 
fairly  dry.  The  outlines  of  the  cup  should  be  regular,  and  all 
sides  should  be  of  approximately  the  same  height.  There  should 
be  no  loose  strands  to  the  wick,  which  should  be  perfectly  smooth 
from  base  to  end. 

The  flame  tip  should  be  smooth,  rounded  and  without  smoke. 
The  height  of  the  flame  will  furnish  indication  as  to  whether  the 
candle  will  burn  faster  or  slower  than  the  standard  time.  The 
candles  should  project  from  one  inch  to  ij  inches  above  the 
holder,  and  care  should  be  taken  to  see  that  they  are  vertical. 

One  of  the  greatest  troubles  with  candles  is  the  fact  that  so 
often  they  cannot  be  made  to  burn  within  the  required  limits, 
and  consequently  the  test  has  to  be  discarded.  Candles  that 
persistently  err  in  this  respect  should  be  unhesitatingly  discarded, 
but  the  cause  is  sometimes  due  to  a  local  condition  and  may  be 
remedied. 

A  hot,  ill  ventilated  room  will  generally  cause  the  candles  to 
burn  slow,  and  after  airing  out  they  will  often  assume  their  nor- 


54  GAS   AND    GAS   METERS 

mal  rate.  If  the  cup  is  too  full  of  sperm  the  candle  will  be  slow. 
This  may  sometimes  be  remedied  by  drawing  out  some  of  the 
liquid  with  a  piece  of  blotting  paper.  If,  however,  the  cup  per- 
sists in  filling,  the  candle  should  be  discarded. 

If  the  rate  of  consumption  is  too  great  it  may  occasionally  be 
lowered  by  taking  the  candle  from  the  holder  and  inverting  over 
the  waste  box  while  still  lighted,  as  in  the  case  of  preparing  a 
fresh  candle  for  use.  If  the  end  of  the  wick  refuses  to  glow,  as 
is  often  the  case  after  it  has  been  touched  or  improperly  extin- 
guished, let  a  drop  of  sperm  carefully  fall  on  the  very  tip  and 
wait  15  or  20  minutes;  the  glow  will  generally  reappear  after 
such  treatment. 

If  there  are  loose  fibers  projecting  from  the  wick,  or  if  it  does 
not  curve  properly,  the  only  thing  to  do  is  to  cut  it  off  close  to 
the  candle  and  prepare  the  latter  afresh,  as  if  it  had  not  been 
used.  In  case  the  wick  is  not  very  nearly  in  the  center  of  the 
candle,  the  latter  should  be  at  once  discarded. 

The  candle  should  be  allowed  to  burn  from  15  to  20  minutes 
before  a  test  is  commenced,  in  order  that  they  may  assume  their 
normal  rate.  It  will  mean  a  very  considerable  saving  of  time 
if  the  operator  will  study  the  candle  flames  and  learn  to  tell  when 
they  are  approximately  normal.  This  judgment  can  be  acquired 
with  some  practice,  and  its  employment  is  vastly  superior  to  the 
custom  of  making  a  test  at  whatever  rate  the  candles  may  be 
burning  and  then  being  obliged  to  discard  the  results  because  the 
rate  of  sperm  consumption  was  abnormal. 

It  is  always  well  to  see  that  the  flames  of  both  candles  and  gas  are 
opposite  the  center  of  the  disc,  and  this  may  be  easily  accomplished 
by  holding  a  pocket  mirror  before  the  disc  and  inclined  at  a  slight 
angle  thereto.  The  reflection  in  this  mirror  will  serve  to  show 
whether  all  of  the  light  from  the  flames  is  reaching  the  disc,  and 
whether  either  gas  or  standard  is  too  high  or  too  low. 

Assuming  now  that  the  above  details  have  been  attended  to,  the 
actual  operations  of  the  test  may  be  taken  up.  Darken  the  room 
and  shut  off  all  drafts.  If  a  closed-bar  photometer  is  being  used 
the  door  of  the  gas  end  should  be  closed,  or  nearly  so.  It  does  no 


CANDLEPOWER   TESTS  55 

harm  in  a  darkened  room  to  leave  this  door  ajar,  and  it  has  the 
advantage  of  improving  the  ventilation.  Adjust  the  balance  so 
that  the  candle  end  is  slightly  the  heavier,  and  with  stop  watch  in 
hand  watch  for  the  swing.  As  the  pointer  passes  the  center  of  the 
scale  start  the  watch,  drop  the  2o-grain  weight  gently  into  the  pan, 
and  close  the  door,  if  there  be  one.  In  case  of  a  lo-minute  test 
with  two  candles,  a  40-grain  weight  should  be  used,  and  with  a 
5-minute  test  and  but  one  candle  the  weight  should  be  only  10 
grains. 

At  the  expiration  of  exactly  30  seconds  from  the  starting  of  the 
watch,  read  the  meter  and  record  the  result.  In  making  readings 
of  the  disc,  set  the  latter  where  the  two  sides  have  a  nearly  equal 
illumination,  and  then  move  so  that  first  one  side  and  then  the 
other  seems  brighter  by  distinct  but  decreasing  amounts,  until  the 
point  is  reached  where  the  illumination  of  both  sides  is  exactly 
the  same.  Record  the  reading  of  the  pointer  on  the  scale  and 
repeat  the  operation  from  10  to  20  times  at  regular  intervals 
throughout  the  period  of  test,  reversing  the  disc  for  the  last  half 
of  the  time. 

This  reading  is  the  most  difficult  part  of  the  operation  to  the 
unexperienced,  and  nothing  but  practice  will  develop  an  expert. 
There  are,  however,  a  few  suggestions  to  be  made  which  may  prove 
of  service.  In  the  first  place,  never  look  at  any  strong  light  just 
prior  to  making  readings.  The  retina  of  the  eye  is  extremely  sen- 
sitive and  will  retain  the  impression  of  the  light  to  such  an  extent 
that  any  accurate  comparison  of  intensities  is  impossible.  The 
writer  makes  it  a  practice  to  discard  his  first  reading,  since,  even  if 
no  strong  light  has  been  viewed,  the  eye  requires  a  moment  or  two 
to  accommodate  itself  to  the  comparative  darkness  of  the  sight 
box. 

Again,  it  is  well  to  make  the  readings  rather  rapidly,  for  the  eye 
soon  becomes  fatigued  with  the  strain  of  comparing  intensities;  for 
this  reason  the  observer  who  takes  a  long  time  for  each  reading  in 
the  hope  of  making  it  absolutely  correct  is  liable  to  obtain  poorer 
results  than  the  one  who  reads  more  rapidly. 

In  moving  the  sight  box  care  must  be  taken,  especially  with  the 


56  GAS   AND    GAS    METERS 

closed-bar  photometer,  that  its  motion  is  not  fast  enough  to  cause  a 
draft  and  thus  produce  flickering  of  the  candles. 

The  observer  is  cautioned  not  to  mistake  difference  in  color  for 
difference  in  intensity,  since  the  color  of  the  gas  flame  is  different 
from  that  of  any  of  the  standards  used.  He  should  not  try  to 
observe  both  sides  of  the  disc  at  once;  the  best  comparison  is  made 
by  viewing  one  side  and  then  the  other  as  rapidly  as  possible  and 
mentally  comparing  the  impressions. 

At  the  end  of  exactly  4  minutes  and  30  seconds  the  reading  of  the 
meter  is  again  taken,  and  then  the  balance  must  be  constantly 
watched  until  the  pointer  again  passes  the  center  of  the  scale,  when 
the  watch  is  stopped  and  its  reading  recorded.  If  on  looking  over 
the  figures  it  is  found  that  the  gas  has  not  burned  very  close  to  the 
five-foot  rate,  that  the  readings  with  a  two-candle  balance  have 
varied  by  more  than  0.5  candle,  or  that  the  rate  of  the  candles  is 
more  than  15  seconds  from  the  normal,  the  test  should  be  repeated. 
With  a  two-candle  standard  there  should  be  no  difficulty  in  obtaining 
consecutive  tests  which  check  within  0.3  to  0.4  candlepower,  and 
very  much  better  than  this  can  usually  be  done  by  a  skilled  observer. 

In  extinguishing  the  candles,  let  fall  a  drop  of  sperm  on  the  glow- 
ing end  of  each  wick  and  immediately  blow  out  the  flame.  This  is 
very  important  and  will  leave  the  candle  in  such  condition  that  on 
relighting  it  will  soon  reach  its  normal  rate. 

Calculations.  There  are  two  or  three  methods  of  making  the  cal- 
culations; in  one,  factors  for  the  various  corrections  are  found  by 
consulting  tables  prepared  for  the  purpose  and  similar  to  the  one 
in  the  appendix;  another  uses  the  candlepower  computer,  on  which 
it  is  only  necessary  to  set  various  results  against  each  other  on  the 
two  scales  and  the  corrected  candlepower  may  at  once  be  read  off; 
while  a  third  method  consists  in  the  use  of  percentages  entirely. 
The  first  two  processes  are  in  far  more  general  use  than  the  third, 
and  the  only  claims  against  them  are  that  they  are  not  especially 
easy  to  understand  and  manipulate  and  that  to  use  them  in  more 
than  one  place  means  the  necessity  of  carrying  tables  or  computer 
always  on  the  person.  The  percentage  method,  while  theoretically 
not  quite  as  accurate,  is  far  simpler,  requires  no  tables  or  other 


CANDLEPOWER   TESTS  57 

paraphernalia,  and  gives  results  which  are  far  more  accurate  than 
many  of  the  factors  in  the  candlepower  determination.  As  the  first 
two  methods  have  been  described  many  times,  they  will  not  be  dealt 
with  here,  but  the  third  method  will  be  explained  and  used  through- 
out this  volume. 

There  are  four  corrections  to  be  applied  to  the  average  of  the 
disc  readings  before  the  corrected  result  can  be  obtained:  (i)  for 
the  temperature;  (2)  for  the  barometer;  (3)  for  the  rate  of  the 
gas;  (4)  for  the  rate  of  the  candles.  The  standard  conditions 
of  temperature  and  pressure  are  60°  F.  and  30  inches  pressure, 
and  if  we  measure  the  gas  under  any  other  conditions,  it  is  clear 
that  we  are  not  getting  the  actual  volume. 

Thus,  consider  for  a  moment  i  cubic  foot  of  gas  A  B  C  D 
under  standard  conditions.  Suppose  now  that  keeping  the  pres- 
sure constant  we  increase  the  temperature 
from  60  to  70°  F.  The  result  will  be  that 
the  gas  will  expand  and  that  the  original 
cubic  foot  will  now  occupy  a  greater  volume, 
as  A  B  E  F.  The  result  would  have  been  the 
same  if,  keeping  the  temperature  constant, 
the  pressure  had  been  reduced  a  certain 
amount.  Now,  when  the  gas  volume  is  read 
on  the  meter  at  70  degrees,  the  result  is  . 

'  '  Fig.    12.      Illustrating 

A  B  E  F,  or,  for  example,  5.13  feet,  whereas,     Expansion  of  Gases, 
really,  but  5  feet  of  gas  have  been  consumed. 
If  the  corrections   are    made   on  the  assumption  that  5.13  feet 
has  been  the  rate,  we  are  obviously  doing  the  gas  an  injustice, 
and   must  add   to  our  result  an   amount  sufficient  to  counter- 
balance this. 

It  has  been  found  by  calculation  and  experiment  that  with  gas 
saturated  with  moisture,  as  is  practically  the  case  after  passing 
the  wet  meter,  a  correction  of  i  per  cent  must  be  made  for  every 
0.3  inch  variation  of  the  pressure  from  30  inches,  and  also 
i  per  cent  for  every  4  degrees  variation  of  the  temperature  from 
60  degrees.  From  what  has  been  said  above,  it  will  be  clear 
that  these  corrections  are  to  be  added  if  the  temperature  is  above 


58  GAS   AND   GAS   METERS 

60  degrees  or  if  the  barometer  is  below  30  inches;  and  vice  versa, 
they  are  to  be  subtracted  if  the  temperature  is  below  60  degrees 
or  the  barometer  above  30  inches.  The  correction  of  i  per  cent 
for  every  4  degrees  of  temperature  does  not  strictly  hold  above 
77°  F.,  but  as  gas  is  seldom  tested  at  temperatures  greater  than 
that,  and  as  the  error  only  reaches  tenths  of  a  per  cent,  the  result 
is  well  within  the  general  limits  of  accuracy  of  the  process. 

With  the  candles  a  correction  of  i  per  cent  for  every  3  seconds 
above  or  below  the  standard  of  5  minutes  for  burning  10  grains 
is  customary.  This  is  derived  as  follows:  One  candle  should 
burn  120  grains  per  hour,  or  10  grains  in  5  minutes;  5  minutes 
equals  300  seconds,  and  i  per  cent  of  300  seconds  is  3  seconds. 
If  the  candles  are  fast,  that  is,  if  they  consume  20  grains  in  less 
than  5  minutes,  they  are  evidently  giving  out  more  light  than 
they  should,  and  consequently  making  the  readings  lower  than 
they  would  be  with  normal  candles;  therefore,  for  fast  candles, 
the  correction  should  be  added,  and  for  slow  ones  it  should  be 
subtracted. 

If  the  gas  burns  faster  than  5  feet  per  hour,  it  is  giving  out 
more  light  than  it  would  under  standard  conditions,  therefore 
a  minus  correction  is  necessary,  and  this  is  figured  out  in  the  fol- 
lowing way:  Subtract  5  feet  from  the  number  of  feet  consumed 
per  hour,  multiply  the  difference  by  100,  divide  by  5,  and  the 
result  will  be  the  percentage  to  be  subtracted. 

A  concrete  illustration  will  make  the  above  remarks  clearer.  The 
following  figures  represent  the  data  secured  in  an  actual  test. 

Temperature  of  gas,  70°  F. 

Barometer,  30.12  inches. 

Two  candles  burned  20  gr.  in  4  minutes  48  seconds. 

Average  reading  on  the  bar,  8.50. 

Reading  of  meter  at  end  of  4  minutes,  0.502 

Reading  of  meter  at  start,  0.166 

Difference,  0.336  foot. 

If  the  gas  consumed  in  4  minutes  was  0.336  foot,  hi  one  hour 
the  rate  would  be  0.336  times  15,  or  5.04  feet;  (5.04  minus  5.00) 
times  100  divided  by  5  equals  0.8  per  cent  minus.  The  tem- 


CANDLEPOWER   TESTS  59 

perature  is  10  degrees  over  60;  10  divided  by  4  equals  2.5  per 
cent  plus.  The  candles  burned  in  12  seconds  less  than  5  min- 
utes; 12  divided  by  3  equals  4  per  cent  plus.  The  barometer  is 
0.12  inch  over  30  inches;  .12  divided  by  .3  equals  .4  per  cent 
minus.  The  corrections  for  rate  of  gas  and  for  barometric  pres- 
sure are  minus,  while  those  for  temperature  and  candles  are 
plus.  Combining  these  we  get  5.3  per  cent  plus,  and  dividing 
the  average  readings  by  i.oo  minus  .053,  the  corrected  reading 
is  found  to  be  8.98;  and  since  a  two-candle  standard  was  used, 
the  true  candlepower  is  8.98  times  2,  or  17.96. 

In  this  example  it  has  been  assumed  that  the  meter  read  in 
thousandths  of  a  foot,  that  a  two-candle  balance  was  used,  that 
the  scale  read  direct  in  candlepower  for  a  one-candle  standard, 
and  that  a  5-minute  test  was  made.  If  only  one  candle  had  been 
employed,  a  lo-grain  weight  would  have  been  used  instead  of 
the  2o-grain,  and  the  readings  would  have  been  twice  as  great. 
Occasionally  a  scale  reads  direct  in  candlepower  for  a  two-candle 
standard,  and  in  such  cases  the  multiplication  of  the  corrected 
reading  by  2  is,  of  course,  omitted. 

If  a  leak  is  discovered  at  the  close  of  the  test,  allowance  must 
be  made  for  it  in  the  calculations.  This  is  done  by  finding  the 
amount  of  the  leak  as  read  from  the  meter  in  4  minutes,  and 
deducting  it  from  the  gas  consumed  during  the  4-minute  test, 
since  this  leakage  gas  did  not  help  in  any  way  to  increase  the 
candlepower,  and  yet  was  included  in  the  calculation  of  the 
amount  of  gas  burned  per  hour. 

The  figures  which  are  likely  to  be  met  in  a  lo-minute  test,  with 
the  meter  divided  into  twelve  hundredths  of  a  foot,  and  a  two- 
candle  standard,  can  best  be  seen  from  the  following: 

Temperature,  56°  F. 

Barometer,  29.73  inches. 

Average  readings  on  bar,  10.17. 

Time  to  burn  40  grains  of  sperm,  10  minutes  12  seconds. 

Reading  of  meter  at  end  of  9  minutes,    1.555 

Reading  of  meter  at  start,  0-637 

Difference,  0.918 


6o  GAS   AND   GAS   METERS 

Rate  of  gas  equals  918/1200  times  60/9  equals  5.1  feet  per  hour. 
Correction  for  gas,  (5.1  minus  5)  times  100  divided  by  5  equals 
2.0  per  cent  minus.  Correction  for  the  candles  (i  per  cent  for 
6  seconds  on  a  lo-minute  test),  2  per  cent  minus.  Correction  for 
temperature,  i  per  cent  minus  and  for  barometer  0.9  per  cent  plus. 
Combined  correction,  4.1  per  cent  minus.  The  corrected  candle- 
power  equals  (jo.ij  times  2)  divided  by  (i.oo  plus  .041)  equals 

I9-54. 

The  lo-minute  test  is  very  generally  employed  and  has  certain 
supposed  advantages  as  to  accuracy;  the  5-minute  test  is  the  one 
employed  by  the  state  inspectors  in  New  York  and  Massachusetts 
and  in  many  municipalities,  and  has  the  advantage  of  economy 
of  time  (which  is  especially  important  to  a  traveling  inspector) 
and  also  of  decreasing  somewhat  the  difficulties  encountered  in 
the  use  of  candles. 


CHAPTER   IV. 
PHOTOMETRIC  WORK  WITH  OTHER  STANDARDS  AND  GASES. 

Pentane  Lamp.  The  Pentane  lamp  has  been  described  in  an 
earlier  chapter,  and  it  is  now  only  necessary  to  study  its  prepara- 
tion for,  and  use  during  a  test.  The  first  thing  is  to  see  that  the 
pentane  to  be  employed  is  of  the  proper  quality.  The  prepara- 
tion and  testing  of  this  compound  cannot  be  better  described 
than  by  quoting  from  the  "  Notification  of  the  Metropolitan  Gas 
Referees  "  for  1907. 

"  Preparation.  —  Light  American  petroleum  such  as  is  known 
as  gasoline  and  used  for  making  air  gas,  is  to  be  further  rectified 
by  three  distillations,  at  55°  C.,  50  and  45  degrees  in  succession. 
The  distillate  at  45  degrees  is  to  be  shaken  up  from  time  to  time 
during  two  periods  of  not  less  than  three  hours  each  with  one- 
tenth  of  its  bulk  of  (i)  strong  sulphuric  acid;  (2)  solution  of 
caustic  soda.  After  these  treatments  it  is  to  be  again  distilled, 
and  that  portion  is  to  be  collected  for  use  which  comes  over  between 
the  temperatures  of  25  and  40  degrees.  It  will  consist  chiefly  of 
pentane,  together  with  small  quantities  of  lower  and  higher  homo- 
logues  whose  presence  does  not  affect  the  light  of  the  lamp. 

"  Testing.  —  The  density  of  the  liquid  pentane  at  15°  C.  should 
not  be  less  than  0.6235,  nor  more  than  0.626,  as  compared  with 
that  of  water  of  maximum  density.  The  density  of  the  pentane 
when  gaseous  as  compared  with  that  of  hydrogen  of  the  same 
temperature  and  under  the  same  pressure,  may  be  taken.  This 
is  done  most  readily  and  exactly  by  Gay-Lussac's  method  under  a 
pressure  of  about  half  an  atmosphere  and  at  temperatures  between 
25  and  35  degrees.  The  density  of  gaseous  pentane  should  lie 
between  36  and  38. 

"Any  admixture  with  pentane  of  hydrocarbons  belonging  to 
other  groups  and  having  a  higher  photogenic  value,  such  as  ben- 

61 


62  GAS   AND    GAS   METERS 

zene  or  amylene,  must  be  avoided.  Their  presence  may  be 
detected  by  the  following  test.  Bring  into  a  stoppered  4-ounce 
bottle  of  white  glass  10  c.c.  of  nitric  acid,  specific  gravity  1.32 
(made  by  diluting  pure  nitric  acid  with  one-half  its  bulk  of  water); 
add  i  c.c.  of  a  dilute  solution  of  potassium  permanganate  con- 
taining o.i  gram  of  permanganate  in  200  c.c. 

"  Pour  into  the  bottle  50  c.c.  of  the  sample  of  pentane,  shake 
strongly  during  5  successive  periods  of  20  seconds.  If  no  hydro- 
carbons other  than  paraffins  are  present,  the  pink  color,  though 
somewhat  paler,  will  still  be  distinct;  if  there  is  an  admixture  of 
as  much  as  one-half  per  cent  of  benzene  or  amylene,  the  color 
will  have  disappeared." 

If  the  lamp  to  be  used  has  been  standardized  by  responsible 
parties,  it  will  have  a  value  assigned  to  it  which  may  be  used  in  all 
calculations;  if  it  has  not  been  authoritatively  standardized,  its 
value  should  be  determined  by  testing  the  lamp  against  candles. 
Since  the  latter  are  liable  to  vary,  it  is  best  to  make  a  large  number 
of  determinations,  using  many  different  candles  in  order  to  arrive 
at  a  correct  result.  The  standardization  is  accomplished  by 
placing  the  lamp  in  the  position  usually  occupied  by  the  gas  pillar, 
with  the  flame  opposite  the  center  of  the  disc  and  with  the  plumb 
bob  suspended  from  the  burner  at  exactly  the  correct  distance 
from  the  center  of  the  scale.  The  determination  is  then  made  in 
the  manner  described  above  for  gas,  save  that  the  only  correc- 
tion to  be  applied  is  for  the  rate  of  the  candles.  The  factor 
thus  derived  will  be  very  close  to  10,  and  should  hold  good  for 
a  year,  provided  no  change  is  made  in  any  of  the  parts  of  the 
lamp. 

The  latter  should  now  be  so  set  up  at  the  end  of  the  bar  oppo- 
site to  the  gas  that  the  bob  hanging  below  the  burner  shall  be  exactly 
in  line  with  those  which  we  have  already  seen  employed  for  the 
alignment  of  the  candles.  The  center  of  the  flame  when  properly 
adjusted  should  be  at  the  same  height  as  the  center  of  the  disc. 
Next  the  instrument  is  to  be  leveled  by  means  of  the  screw  legs  of 
the  tripod ;  this  is  in  order  that  the  burner  and  chimney  may  be  ver- 
tical. After  the  leveling  it  will  doubtless  be  found  that  the  plumb 


PHOTOMETRIC    WORK  63 

bobs  are  no  longer  in  line;  if  so,  this  must  be  rectified.  When  the 
lamp  is  lighted  the  plumb  line  should  bisect  the  flame,  and  this 
should  be  carefully  observed. 

In  filling  the  lamp  remember  first  of  all  that  pentane  is  extremely 
inflammable,  and  see  that  all  flames  are  excluded  from  the  room. 
Open  both  inlet  and  outlet  cocks  to  the  saturator  box,  and  also  the 
drip  cock  at  the  bottom  of  the  vapor  tube.  Fill  the  saturator  two- 
thirds  full  of  pentane  and  close  all  cocks.  The  height  of  the  liquid 
against  the  window  in  the  side  of  the  saturator  should  never  be  less 
than  J  inch.  The  lower  end  of  the  chimney  tube  is  next  set  exactly 
above  the  steatite  ring  burner,  and  47  mm.  distant  therefrom.  This 
is  easily  accomplished  by  means  of  the  boxwood  gauge,  which  is 
furnished  with  the  lamp,  but  before  using  this  gauge  the  conical 
shade  about  the  burner  must  be  removed.  If  the  chimney  is  not 
centrally  over  the  burner,  it  may  be  brought  to  this  position  by 
means  of  the  three  adjusting  screws  in  the  base  of  the  outer  chimney. 
These  screws  should  be  tightened  only  enough  to  maintain  the 
chimney  tube  in  its  central  position.  This  adjustment  being  made, 
the  conical  shade  is  replaced  with  the  opening  so  located  that  all  of 
the  flame  below  the  chimney  may  be  seen  from  the  position  of  the 
disc. 

In  lighting  and  regulating  the  lamp  the  following  instructions  are 
taken  from  the  "Proceedings  of  the  American  Gas  Institute"  for 
October,  1907: 

Lighting.  —  The  regulating  cock  being  closed,  open  first  the 
outlet  cock  on  the  saturator  box;  then  open  the  drip  cock.  At  or 
above  60°  F.,  it  is  likely  that  vapor  pressure  will  have  accumulated 
in  the  saturator.  The  drip  cock  will  permit  its  release  and  fill  the 
tube  with  vapor  ready  for  the  siphon  action  upon  which  the  supply 
of  fuel  depends ;  and  furthermore,  discharge  the  excess  vapor  below 
the  position  of  the  flame. 

The  inlet  cock  is  then  opened  to  establish  atmospheric  pressure 
in  the  saturator,  and  the  drip  cock  is  closed.  Light  a  match  and 
hold  over,  but  not  touching,  the  steatite  burner.  Gradually  open 
the  regulating  cock,  when  the  vapor  will  ignite  gently  if  feeding 
properly. 


64  GAS    AND    GAS    METERS 

Should  there  at  first  be  an  excess  of  air  in  the  burner,  the  flame 
will  burn  with  a  greenish  center,  and  as  the  proper  proportion  of 
the  mixture  is  obtained,  a  small  explosion  will  take  place,  extin- 
guishing it.  Relight  at  once  without  changing  the  regulating  cock, 
when  the  flame  will  burn  normally. 

Its  shape  at  first  will  be  purely  conical,  but  as  the  hot  air  inner 
feed  increases,  the  cone  will  be  bulged,  and  its  top  will  open  into 
a  ring. 

Regulating.  —  During  the  15  minutes  while  the  flame  is  maturing, 
or  the  lamp  reaching  a  thermal  equilibrium,  the  flame  should  be, 
from  time  to  time,  regulated  to  the  height  of  the  crossbar.  If  it  be 
too  low,  it  will  take  longer  to  mature;  if  it  be  too  high,  it  will  smoke 
the  chimney.  When  the  flame  remains  steady  and  it  is  time  for  the 
reading,  set  its  height  as  follows:  Move  the  disc  box  near  to  the 
lamp;  stand  in  rear  of  the  lamp,  looking  first  at  the  mica  window 
and  then  past  it  at  the  reflection  of  the  flame  front  in  the  disc  glass. 
Lower  the  flame  top  below  the  chimney.  When  it  is  perfectly 
quiet,  slowly  raise  it  until  its  reflected  image  shows  wholly  luminous 
at  the  base  of  the  chimney.  This  is  the  position  of  maximum  inten- 
sity of  the  flame.  A  further  rise  of  one-fourth  inch  will  not  mate- 
rially affect  the  value  of  the  lamp.  The  flame  top  draws  to  three 
luminous  points.  If  the  lamp  is  free  from  drafts  and  the  air  is 
pure,  the  flame  height  will  be  approximately  correct  when  these 
points  are  at  the  height  of  the  crossbar  in  the  American  lamp.  The 
lamp  is  now  ready  for  use. 

Now,  having  aligned  the  gas  burner,  and  rated  the  flow  of  gas  to 
5  feet  per  hour,  start  the  watch  as  the  long  hand  of  the  meter  passes 
some  particular  point  on  the  dial  and  record  the  reading.  Make 
from  10  to  20  readings  of  the  disc,  reversing  the  latter  for  the  last 
half  of  them.  Note  and  record  the  reading  of  the  meter  after 
exactly  5  minutes  have  elapsed.  The  corrections  for  barometer, 
temperature  and  rate  of  gas  are  now  applied  to  the  average  read- 
ings in  exactly  the  same  manner  as  when  the  candles  are  used  as  a 
standard;  but  the  corrected  reading  thus  obtained  must  then  be 
multiplied  by  the  value  of  the  lamp,  and  this  result  will  be  the  true 
candlepower  of  the  gas. 


PHOTOMETRIC    WORK  65 

Example.  Value  of  the  lamp,  9.95  candles;  average  readings 
on  the  bar,  1.84;  temperature,  62  degrees;  barometer,  30.24  inches; 
gas  burned  in  5  minutes,  5.12  revolutions  of  the  large  hand,  or 
iVA  °f  a  f°°t-  The  corrections  are:  Temperature,  0.5  per  cent 
plus;  barometer,  0.8  per  cent  minus;  gas,  2.4  per  cent  minus; 
total,  2.7  per  cent  minus.  (1.84  -r-  1.027)  X  9.95  =  17.81,  the  cor- 
rected candlepower.  In  extinguishing  the  lamp  simply  close  all 
of  the  cocks,  commencing  with  the  inlet  cock  to  the  burner. 

Elliott  Lamp.  The  fuel  recommended  for  use  with  this  lamp 
is  Pratt' s  astral  oil,  a  variety  of  kerosene  which  does  not  need  to 
be  tested,  both  because  of  its  general  uniformity  and  because  any 
variation  in  the  oil  would  make  but  little  difference,  since  the  lamp 
is  filled  and  standardized  each  day.  The  filling  is  accomplished 
in  the  same  manner  as  with  the  old-fashioned  student  lamp.  The 
chimney  must  be  thoroughly  cleaned  each  time  before  use,  and  it 
is  well  to  select  a  certain  side  which  shall  always  be  presented 
towards  the  disc.  If  a  fresh  wick  is  to  be  used,  place  the  sheet 
brass  pattern  which  comes  with  the  lamp  over  the  wick  and  trim 
to  conform  to  this  pattern.  Singe  the  top  of  the  wick  to  free  it 
from  fluff  and  to  secure  a  smooth,  even  surface.  If  the  wick  has 
been  used  before,  trim  the  top  very  carefully  with  a  pair  of  sharp 
shears,  taking  great  pains  to  remove  only  the  soft  carbon  and  not 
to  cut  into  the  wick  itself.  The  wick  should  be  changed  at  least 
once  a  week,  as  experiments  made  by  the  writer  show  that  the 
lamp  depreciates  in  value  and  loses  its  constancy  even  over  a  period 
of  12  hours  where  the  wick  is  old.  Place  the  lamp  at  the  standard 
end  of  the  photometer;  light  the  same  and  let  it  burn  quietly 
for  10  minutes.  Bring  the  flame  in  line  with  the  plumb  lines, 
opposite  the  center  of  the  disc  and  perpendicular  to  the  axis  of 
the  photometer.  Then  adjust  the  flame  so  that  the  top  thereof 
is  not  over  one-quarter  of  an  inch  above  and  parallel  with  the 
upper  edge  of  the  diaphragm. 

If  properly  trimmed  and  set,  nothing  but  the  luminous  part  of 
the  flame  should  be  visible  through  the  diaphragm;  it  usually 
happens,  however,  that  the  blue  portion  rises  slightly  above  the 
lower  edge  of  the  opening,  and  this  cannot  be  prevented.  If  the 


66  GAS   AND    GAS    METERS 

center  of  the  flame  rises  too  high,  it  may  be  remedied  by  trimming 
the  top  of  the  wick  a  trifle  concave.  After  the  flame  is  properly 
adjusted,  allow  the  lamp  to  burn  20  minutes  before  commencing 
the  test,  which  is  conducted  in  exactly  the  manner  described  for 
the  Pentane  lamp,  and  the  calculations  are  the  same,  so  that  these 
need  not  be  repeated  here. 

Edgerton  Standard.  The  most  important  factors  in  connection 
with  the  use  of  this  standard  are  to  see  that  it  is  properly  and 
frequently  standardized  and  that  the  chimney  is  kept  clean.  If 
convenient,  it  is  desirable  that  the  gas  used  in  the  standard  should 
not  vary;  this  may  be  accomplished  by  filling  a  small  holder  with 
gas  of  uniform  quality.  Either  water  gas  or  coal  gas  may  be  used, 
but  it  must  be  remembered  that  the  value  of  the  standard  will 
not  be  the  same  for  the  two.  In  standardizing,  place  a  definite 
portion  of  the  chimney  towards  the  disc,  and  in  all  future  work 
keep  the  same  portion  in  that  position.  The  flame  is  to  be 
3  inches  high,  though  a  slight  variation  from  this  will  not  materially 
affect  the  results.  The  work  of  ascertaining  the  value  of  the 
Edgerton,  together  with  its  use  as  a  standard,  is  so  similar  in 
principle  to  the  methods  described  for  the  Pentane  and  Elliott 
lamps,  that  it  does  not  seem  necessary  to  go  into  detail  regarding 
them.  . 

Hefner  Lamp.  The  fuel  used  in  this  is  a  chemical  compound 
known  as  amyl  acetate  and  will  as  a  rule  be  purchased  ready  for 
use,  since  its  preparation  and  purification  at  the  works  or  laboratory 
of  the  inspector  would  in  the  end  prove  costly.  Amyl  acetate  has 
the  formula  C5HU.C2H3O,  and  may  be  called  the  amyl  ether  of 
acetic  acid.  It  boils  at  148°  C.,  and  consequently  is  very  much 
less  inflammable  than  pentane.  Its  specific  gravity  is  0.874;  it  is 
soluble  in  alcohol  and  ether,  but  not  in  water.  It  should  be  possible 
to  secure  this  chemical  in  a  perfectly  pure  condition,  but  if  there 
is  any  doubt  on  this  point  it  may  be  settled  by  testing  its  gravity 
and  boiling  point,  and  if  impurities  be  present,  they  may  be 
eliminated  by  fractional  distillation. 

In  addition  to  the  above  tests  the  "  Physikalische  Technische 
Reichsanstalt "  recommends  the  following:  When  distilled  in  a  glass 


PHOTOMETRIC   WORK  6/ 

retort  at  least  90  per  cent  should  pass  over  between  the  temperature 
limits  of  137  and  143°  C.  Its  reaction  should  be  practically  neutral, 
and  blue  litmus  paper  should  not  be  sensibly  reddened  by  it.  It 
should  mix,  bulk  for  bulk,  with  ether,  benzine  or  carbon  bisulphide 
without  becoming  milky.  A  drop  placed  on  white  filter  or  blotting 
paper  should  evaporate  without  leaving  a  greasy  spot.  It  should 
be  kept  in  a  glass-stoppered  bottle  and  in  a  dark  place,  as  it  has 
a  tendency  to  decompose  in  a  strong  light. 

Stine,  in  his  "  Photometrical  Measurements,"  gives  the  following 
description  of  the  proper  method  of  operating  the  Hefner  lamp: 
The  character  of  the  wick  is  practically  without  influence  on  the 
illuminating  power  of  the  lamp  if  it  does  not  fill  the  tube  tightly. 
The  wick  should  be  washed  in  distilled  water,  then  soaked  for  a 
time  in  a  i  or  2  per  cent  solution  concentrated  ammonia,  and 
finally  thoroughly  washed  in  distilled  water. 

To  prepare  the  lamp  for  use,  insert  the  wick  in  the  wick  tube 
and  test  the  adjusting  wheel  train,  which  must  move  the  wick 
easily  and  smoothly  without  catching  in  its  threads  or  sticking. 
Then  the  top  of  the  wick  should  be  trimmed  off  straight  and 
smooth  with  the  top  of  the  tube,  using  sharp  scissors  and  avoiding 
irregularity  of  surface  or  stray  thread  ends.  The  top  of  the 
lamp  is  unscrewed,  and  the  amyl  acetate  is  poured  into  the  lamp 
until  it  is  nearly  filled,  leaving  sufficient  space  so  that  the  addition 
of  the  wick  will  not  cause  an  overflow.  Screw  the  top  in  place, 
and  after  the  wick  has  become  thoroughly  wet,  light  it,  adjust  the 
flame  to  the  normal  height,  and  place  the  lamp  in  position  on  the 
photometer  bench.  Allow  it  to  burn  for  20  to  30  minutes  in  order 
to  become  constant.  The  vent  holes  on  the  top  plate  near  the 
wick  tube  must  be  watched  and  kept  open. 

As  soon  as  the  determination  is  completed,  the  lamp  should  be 
emptied  and  cleaned,  for  the  metallic  parts  are  liable  to  corrosion 
from  the  action  of  decomposition  products  of  the  amyl  acetate. 
The  wick  should  be  removed  and  the  lamp  and  wick  tube  well 
rinsed  with  ordinary  alcohol.  The  wick  itself  is  to  be  thoroughly 
washed  in  clean  alcohol,  dried  and  stored  in  a  tightly  stoppered 
test  tube.  The  amyl  acetate  which  is  poured  from  the  lamp  after 


68  GAS   AND   GAS   METERS 

a  determination  should  be  thrown  away  and  not  used  for  another 
test.  This  does  not  mean  a  great  waste,  for  unless  the  lamp  is  to 
be  used  over  a  long  period  it  need  not  be  completely  filled  at  the 
start,  as  Dr.  Stine's  procedure  would  indicate.  If  but  one  test  is 
to  be  made,  a  very  small  amount  of  amyl  acetate  will  answer, 
since  so  long  as  the  ends  of  the  wick  all  rest  in  the  fluid,  the 
supply  is  sufficient  for  the  flame.  Repetition  must  also  be  made 
of  two  of  the  precautions  already  mentioned,  as  they  are  extremely 
important:  (i)  See  that  the  flame  height  is  exactly  correct. 
(2)  Allow  no  draft  or  jar  to  affect  the  test. 

Candlepower  Tests  of  Other  Gases.  While  the  general  procedure 
for  taking  the  candlepower  of  acetylene,  oil,  gasolene  and  natural 
gases  is  the  same  as  has  already  been  described  for  coal  and 
water  gas,  there  are  certain  points  of  difference,  especially  with 
respect  to  the  burners  employed,  which  it  may  be  well  to  note 
here.  With  a  straight  oil  gas  whose  candlepower  will  be  from 
45  to  60,  none  of  the  burners  hitherto  mentioned  will  give  satis- 
factory results,  due  doubtless  to  the  fact  that  not  one  of  them 
provides  the  proper  amount  of  air  for  combustion.  A  3 -foot  iron 
tip  burner  has  been  found  by  the  writer  to  give  excellent  results, 
and  is  therefore  recommended  for  this  quality  of  gas.  It  is  clear 
that  the  rate  of  consumption  in  such  a  burner  cannot  even 
approximate  5  feet  per  hour,  and  it  has  been  demonstrated  by 
experiment  that  the  highest  results  are  obtained  when  the  gas  is 
burning  at  a  rate  of  from  0.75  to  i  foot  per  hour.  It  will  often 
be  found  desirable  to  try  more  than  one  rate  in  order  to  be  certain 
of  securing  the  maximum  results,  although  a  practiced  observer 
can  generally  judge  by  his  eye  when  the  flame  has  reached  its 
point  of  greatest  efficiency.  The  correction  for  this  consumption 
of  gas  may  be  applied  in  exactly  the  same  manner  as  previously 
described;  or  the  average  readings,  corrected  for  candles,  barom- 
eter and  temperature,  may  be  multiplied  by  5  and  divided  by  the 
rate  per  hour. 

In  testing  acetylene  great  precautions  must  be  taken  to  guard 
against  leaks  or  escape  of  gas,  since  it  is  an  extremely  explosive 
substance.  Like  oil  gas,  it  requires  a  special  burner  consuming 


PHOTOMETRIC   WORK  69 

about  i  foot  per  hour,  and  on  account  of  the  wide  limits  of  its 
explosibility  with  air,  peculiar  provisions  have  to  be  made  to 
insure  the  presence  of  only  the  requisite  amount  of  air.     There 
are    several   burners   on  the  market  which  have 
solved   these    problems,   and   of   these   either    the 
Perfection  No.  3  or  the  Bray  burner  will  give  very 
good  results,   although  the  former  yields  slightly 
the  higher  candlepower.     The  Perfection  burner, 
however,  must  not  be  turned  down  or  it  will  car- 
bonize, while  the  other  may  be  regulated  without 
this    objection.      The   burners    are  very  delicate, 
and  should  be  watched  to  see  that  the  lava  is  not 
chipped  and  that  the  holes  do  not  become  plugged. 
If  the  latter  occurs,  use  great  care   in   cleaning  Acetylene  Burner, 
them  in  order  not  to  enlarge  the  aperture  or  chip 
the  edge.     The  rate  to  be  employed  with  these  burners  is  i  foot 
per  hour,  and  the  correction  is  made  as  in  the  case  of  the  oil 
gas. 

With  gasoline  gas  the  Tirrill  burner  seems  to  give  the  best 
results,  and  the  rate  of  consumption  with  this  should  be  about 
6  feet  per  hour. 

Natural  gas  is  seldom  tested  for  illuminating  power,  since  it  is 
almost  entirely  used  in  Welsbach  mantles  and  heating  appliances. 
The  writer  has,  however,  made  a  few  tests  of  such  gas  for  candle- 
power  and  secured  very  satisfactory  results  with  the  new  F  Argand 
burner.  It  was  impossible,  however,  to  make  the  tests  at  the  5- 
foot  rate,  and  the  gas  was  turned  down  so  as  to  fill  about  half 
the  chimney,  and  the  proper  correction  made  for  this  reduction  of 
rate.  The  gas  as  tested  burned  3.2  feet  per  hour,  and  the  blue 
part  of  the  flame  was  unusually  high. 


CHAPTER    V. 
INTERPRETATION  OF  RESULTS  AND  LEGAL  REQUIREMENTS. 

WHILE  this  work  is  in  no  sense  intended  as  a  treatise  on  the 
manufacture  of  gas,  it  cannot  entirely  ignore  that  subject.  The 
mere  figures  denoting  the  candlepower  are  valueless  unless  deduc- 
tions can  be  drawn  therefrom  which  will  result  in  increased  effi- 
ciency and  economy  at  the  works.  It  would  seem,  therefore, 
that  no  apology  was  necessary  for  discussing  some  of  the  more 
important  factors  affecting  candlepower,  in  order  that  the  photo- 
meter may  prove  to  the  manager  a  true  and  useful  friend. 

Taking  first  the  question  of  coal  gas,  the  coal  used  is  of  course 
one  of  the  most  important  factors.  Where  the  laboratory  facilities 
permit,  it  is  very  desirable  that  every  fresh  shipment  of  coal  should 
be  analyzed,  and  if  possible  some  contract  made  with  the  coal 
company  which  should  bind  the  latter  to  certain  specifications. 
If  such  analysis  is  made,  the  principal  attention  should  be  de- 
voted to  the  fixed  carbon,  volatile  matter,  moisture  and  sulphur, 
since  the  first  three  of  these  affect  the  quantity  and  quality  of  gas 
and  coke,  while  the  last  appears  as  a  very  objectionable  impurity 
in  both  gas  and  by-products.  The  coal  as  charged  into  the  retorts 
should  contain  as  little  moisture  as  possible,  as  this  has  a  power- 
ful effect  in  lowering  the  temperature  of  the  retort,  by  reason  of 
the  large  amount  of  heat  absorbed  in  converting  the  water  into 
steam,  or  to  speak  technically,  by  reason  of  the  high  latent  heat 
of  steam. 

The  next  point  to  be  considered  is  with  regard  to  the  yield. 
Ten  years  ago  it  was  not  difficult  to  make  5  feet  or  even  5.25  feet 
of  gas  per  pound  of  coal  and  still  maintain  a  satisfactory  candle- 
power;  but  to-day  such  a  result  seems  to  be  almost  impossible, 
unless  the  plant  is  equipped  with  modern  apparatus,  the  best  of 
gas  coal  is  purchased  and  the  entire  operation  of  gas  making  is 

70 


INTERPRETATION   OF   RESULTS  Jl 

conducted  with  the  greatest  skill.  Otherwise  the  best  practice 
would  indicate  4.75  to  4.9  feet  per  pound  as  the  maximum  safe 
yield. 

If  the  gas  is  to  be  enriched,  however,  a  much  larger  yield  may 
be  obtained,  yet  a  not  inconsiderable  portion  of  candlepower 
difficulties  arises  from  this  very  fact  of  enrichment,  which  was 
intended  to  abolish  them.  It  is  an  old  story  familiar  to  every 
inspector  of  wide  experience;  the  manager  will  state  that  he  has 
enriched  his  gas  and  that  therefore  it  must  be  satisfactory.  Let 
us  examine  this  statement  a  moment. 

The  enrichers  most  commonly  employed  are  cannel  coal,  ben- 
zol and  oil.  Cannel  gives  off  a  very  rich  gas,  and  if  this  be  burned 
at  the  proper  heats  and  well  mixed  with  the  gas  to  be  enriched, 
it  will  serve  its  purpose  admirably.  It  is  possible,  however,  by 
lack  of  attention  to  the  above  points,  to  use  cannel  and  not  secure 
the  desired  results.  This  is  also  true  of  oil  enrichment,  while 
with  benzol  the  increase  of  candlepower  depends  on  two  factors, 
(i)  whether  the  benzol  is  so  cracked  up  and  mixed  with  the  gas  to 
be  enriched  as  to  form  a  permanent  gas;  (2)  whether  the  gas  from 
the  retorts  is  of  the  right  quality  to  carry  the  benzol.  The  writer 
has  seen  tests  of  benzol-enriched  gas  where  the  finished  product 
was  of  no  higher  candlepower  than  the  unenriched  gas,  due  to  the 
fact  that  nearly  all  of  the  enriching  material  was  dropped  from  the 
gas  before  reaching  the  place  of  test. 

The  treatment  which  the  gas  receives  in  the  retorts,  washers, 
etc.,  is  perhaps  the  most  important  factor  governing  the  quality 
of  the  finished  product.  If  the  heats  in  the  retorts  are  low  and 
the  charge  is  not  left  in  too  long,  a  gas  high  in  candlepower  may  be 
secured,  but  the  yield  will  be  too  small.  If  the  heats  are  high  and 
the  exhauster  is  pulling  strongly,  a  large  yield  will  be  obtained, 
but  the  higher  hydrocarbons,  which  are  the  light-giving  factors, 
will  be  decomposed  into  the  lower  forms ;  hydrogen  will  be  liberated 
in  large  amounts  and  the  candlepower  will  suffer. 

Hornby,  in  his  "Gas  Manufacture,"  says:  "As  the  gas  passes 
down  the  heated  retort  on  the  way  to  the  ascension  pipe,  it  comes 
in  contact  with  the  heated  sides  of  the  retort,  and  this  and  the 


GAS   AND    GAS    METERS 


radiant  heat  in  the  retort  cause  the  following  reactions:  Ethane 
splits  up  into  ethylene  and  hydrogen,  while  ethylene  decomposes 
to  methane  and  acetylene,  and  the  latter  at  once  polymerizes  to 
benzene,  styrolene,  retene,  etc.  A  portion  also  condenses  and  at 
the  same  time  losing  some  hydrogen,  becomes  naphthalene;  and 
the  compounds  formed  by  interactions  among  themselves  build 
up  the  remainder  of  the  hydrocarbons  present  in  the  coal  tar, 
while  the  organic  substances  containing  oxygen  in  the  coal  break 
down  and  cause  the  formation  of  the  phenols  in  the  tar.  ...  At 
comparatively  low  temperatures  you  get  plenty  of  tar  and  little 
gas,  the  latter,  however,  of  high  candlepower.  As  the  heat  is 
increased  the  liquid  hydrocarbons  decrease  and  gaseous  products 
increase;  that  is,  you  get  more  gas  and  less  tar.  At  still  higher 
heats  the  gaseous  products  are  richer  in  hydrogen  and  poorer  in 
carbon,  and  methane  is  formed  abundantly.  Finally  at  still 
higher  heats  free  hydrogen  is  given  off,  this  always  occurring 
towards  the  end  of  the  operation  of  gas  making." 

In  the  advanced  course  of  "  Self  Instruction  for  Students  of  Gas 
Manufacture  "  by  Mentor,  the  following  table  is  given  to  show  the 
effect  of  temperature  on  the  composition  of  the  gas. 


Temperature. 

Hydrogen. 

Methane. 

defines. 

Carbon 
Monoxide. 

Nitrogen. 

Dull  red             .            . 

% 
38  OQ 

% 
4.2    72 

% 
7    s=? 

% 
8    72 

% 
2    Q2 

Hotter 

A-I    77 

?4    CQ 

5  8? 

1  2     C.O 

34O 

Bright  orange  

48.  02 

30.70 

4.51 

13.96 

2.8l 

Now  by  considering  the  value  of  each  of  these  constituents  for 
illuminating  purposes,  the  influence  of  the  temperature  in  the 
retorts  may  readily  be  seen.  In  Latta's  "Hand  Book  of  Gas 
Engineering  Practice  "  the  candlepowers  of  four  of  the  principal 
illuminants  are  given  as  follows:  benzene,  349.0;  ethane,  35.0; 
ethylene,  68.5;  methane,  5.0. 

The  Massachusetts  State  Gas  Inspector  in  his  report  of  Feb- 
ruary, 1885,  says:  "80  to  90  per  cent  of  each  gas  is  composed  of 
diluents  or  light  bearers.  These  are  hydrogen,  methane  and 


INTERPRETATION   OF   RESULTS  73 

carbon  monoxide.  None  of  these  give  any  light  when  burned 
alone,  but  do  give  considerable  heat.  Equal  volumes  of  hydro- 
gen and  carbon  monoxide  give  about  equal  quantities  of  heat 
when  burned;  but  methane  gives  about  three  times  as  much 
heat  as  either.  The  heat  furnished  by  these  gases  in  burning 
helps  to  raise  the  temperature  of  the  particles  of  carbon  set  free 
from  the  illuminants  when  these  are  decomposed  by  the  heat  of 
the  flame.  Small  quantities  of  carbon  monoxide  up  to  12  per  cent 
can  be  added  to  coal  gas  and  the  light  will  be  increased  thereby. 
But  if  as  much  as  20  per  cent  of  carbon  monoxide  is  added,  the 
light  is  considerably  diminished.  Hydrogen  may  be  advanta- 
geously present  in  coal  gas  up  to  40  per  cent  of  the  entire  mixture." 
The  effect  of  carbonic  acid  in  gas  has  likewise  been  investigated 
by  the  Massachusetts  inspector,  and  is  shown  in  tables  in  the 
appendix. 

The  value  of  the  gas  as  an  illuminant  also  depends  upon  the 
length  of  time  which  it  takes  to  carbonize  the  charge.  Butter- 
field,  in  his  "Chemistry  of  Gas  Manufacture,"  says:  "The  gas 
evolved  shortly  after  coal  is  placed  in  a  retort  at  an  ordinary 
carbonizing  temperature  contains  the  gases  occluded  in  the  coal. 
These  are  mainly  nitrogen  and  methane,  with  small  quantities  of 
oxygen,  carbonic  acid  and  other  gases;  consequently  the  illumin- 
ating power  of  the  gas  coming  from  the  retort  during  the  first 
half  hour  after  charging  is  very  low.  Then  it  rises  rapidly  and 
the  gas  evolved  during  the  next  hour  is  the  best  obtained  from 
the  charge.  If  the  heat  of  the  retort  is  low,  this  period  is  pro- 
longed, and  the  gas  is  even  richer.  But  from  the  middle  or  end 
of  the  second  hour  to  the  end  of  the  third  hour  it  may  be  taken 
that  the  gas  will  be  considerably  poorer,  and  thence  to  the  end  of 
the  distillation  that  it  will  be  very  poor  indeed.  The  period  at 
which  the  richest  gas  is  produced  is  also  that  of  the  most  rapid 
production,  though  the  rate  of  evolution  does  not  fall  off 
markedly  during  the  ensuing  period." 

The  tendency  of  a  considerable  vacuum  within  the  retorts  is  to 
draw  in  air  and  furnace  gases  through  cracks  in  the  walls  of  the 
retort,  or  through  imperfectly  sealed  lids.  The  effect  of  carbonic 


74  GAS   AND    GAS   METERS 

acid  on  candlepower  has  already  been  mentioned,  and  that  of  air 
may  be  gathered  from  experiments  of  the  Massachusetts  inspec- 
tors, made  in  1893,  which  are  summarized  in  a  table  given  in 
the  appendix.  Experiments  by  Wurtz  gave  even  greater  losses 
of  candlepower  than  are  shown  in  this  table,  running  from  15.69 
per  cent  loss  of  light  for  an  addition  of  3  per  cent  of  air  up  to 
84  per  cent  loss  for  25  per  cent  of  air. 

The  gas  coming  from  the  hydraulic  main  is  at  a  temperature 
of  about  130  to  150°  F.,  and  if  this  were  suddenly  chilled  it  is 
certain  to  drop  a  large  share  of  its  illuminants,  and  even  after 
leaving  the  purifiers  a  sudden  drop  in  temperature  will  cause  a 
loss  of  candlepower  which  is  in  inverse  ratio  to  the  degree  of 
fixation  of  the  gas.  That  is  to  say,  a  gas  in  which  the  hydro- 
carbons are  poorly  cracked  up  will  lose  far  more  in  candlepower 
than  one  where  they  are  well  fixed.  The  amount  of  water  used 
in  the  scrubbers  also  has  an  influence  on  the  candlepower.  If 
in  the  desire  to  remove  all  traces  of  ammonia  a  large  amount  of 
fresh  water  is  used,  the  candlepower  is  liable  to  suffer;  the  remedy 
is  to  repeatedly  run  the  same  water  through  the  scrubber.  This 
will  naturally  be  done  in  any  case  where  the  ammonia  liquor  is 
to  be  sold,  and  the  suggestion  is  made  for  such  of  the  smaller 
plants  as  do  not  recover  their  ammonia. 

Water  gas  is  made  by  passing  steam  through  a  bed  of  incan- 
descent carbon  and  enriching  the  product  by  means  of  oil.  The 
factors  which  in  this  process  tend  to  decrease  the  illuminating 
value  of  the  yield  are:  (i)  the  admission  of  too  large  an  amount 
of  steam;  (2)  insufficient  heat  in  the  generator;  (3)  fires  not 
clean  or  fuel  bed  too  low;  (4)  incorrect  relation  between  blows 
and  runs,  or  wrong  lengths  of  either;  (5)  poor  carburation. 
The  reactions  concerned  in  the  manufacture  of  water  gas  are, 
generally  speaking,  4  in  number. 

(1)  C  +  2H2O  =  CO2  +  2H2. 

(2)  C  +    H2O  =  CO  +  H2. 

(3)  C  +    CO2  =  2  CO. 

(4)  CO  +    H20  =  C02  +  Ha. 


INTERPRETATION   OF   RESULTS  75 

The  first  commences  at  about  600°  C.,  the  second  at  1000  degrees, 
while  the  other  two  are  liable  to  take  place,  to  varying  extents, 
between  700  or  800  degrees  and  1200°  C.  It  is  evident  that  the 
first  and  fourth  reactions  must  be  prevented  if  possible;  the  one 
is  caused  by  a  lack  of  heat  in  the  generator  and  the  other  by  the 
presence  of  too  much  steam  or  too  little  fuel.  As  the  steam  passes 
up  through  the  lower  layers  of  the  fuel,  the  temperature  at  that 
point  is  reduced  and  reaction  one  takes  place. 

The  carbonic  acid  formed,  passing  upward  through  hotter  and 
hotter  layers,  reacts  with  the  carbon  according  to  equation  three, 
and  thus  the  objectionable  carbonic  acid  is  largely  excluded  from 
the  finished  product.  Now,  if  too  much  steam  is  supplied,  it 
means- the  cooling  of  larger  areas  of  the  generator;  the  steam  rises 
intact  to  the  upper  layers  of  fuel,  reactions  two  and  three  are 
prohibited,  while  numbers  one  and  four  are  carried  out,  and  as  a 
result  large  quantities  of  carbonic  acid  pass  over  into  the  car- 
burettor. If  on  the  contrary  the  admission  of  steam  be  too  slow 
the  yield  will  be  small;  so  that  a  happy  medium  must  be  struck 
and  this  can  best  be  found  by  experiment  in  each  individual 
case. 

If  the  fuel  bed  be  too  low  the  carbonic  acid  formed  at  the  bottom 
passes  out  at  the  top  without  having  been  reduced  to  carbon 
monoxide,  and  the  same  effect  is  produced  by  insufficient  heat  in 
the  generator. 

If  the  length  of  the  blow  is  too  great,  there  is  a  waste  of  fuel; 
while  if  it  is  too  short,  the  generator  and  its  contents  are  not  raised 
to  the  temperature  necessary  for  the  vital  reactions. 

If  the  run  be  too  long  the  fuel  bed  becomes  cooled  below  the 
point  at  which  carbon  monoxide  is  formed  and  retained,  and  again 
carbonic  acid  passes  off  in  the  product. 

Thus  it  will  be  seen  that  most  of  these  difficulties  sum  themselves 
up  in  the  words  "carbonic  acid";  consequently  the  gas  should  be 
constantly  tested  for  this  substance,  and  when  it  is  found  to  be 
present  to  the  extent  of  over  3  or  4  per  cent  the  indications  are 
that  some  of  the  above-mentioned  factors  are  at  work.  The 
determination  of  carbonic  acid  is  easily  and  quickly  made  and  the 


76  GAS   AND    GAS   METERS 

various  methods  and  details  will  be  thoroughly  given  in  the  chapter 
on  chemical  tests. 

Air  or  nitrogen  is  nearly  always  present  in  water  gas  to  some 
extent  and  is  due  to  the  amount  left  in  the  generator  at  the  end  of 
a  blow  and  to  the  nitrogen  in  the  coal.  Its  percentage  is  usually 
small,  however,  unless  entering  from  some  other  source,  in  which 
case  the  effect  on  the  candlepower  will  be  marked,  as  has  been 
already  demonstrated  for  coal  gas. 

In  the  superheater  care  must  be  taken  to  see  that  the  heat  is 
sufficient  to  insure  the  permanency  of  the  oil  gas,  otherwise  there 
will  be  a  considerable  loss  of  candlepower,  due  to  condensation 
of  the  oily  vapors.  If  the  generator,  carburettor  and  superheater 
are  in  one,  as  is  the  case  with  some  of  the  older  types  of  apparatus, 
there  is  danger  not  only  of  not  properly  fixing  the  oil  gas,  but  also 
of  maintaining  so  high  a  temperature  that  the  oil  will  break  down 
and  deposit  carbon. 

Chilling  of  the  gas  in  the  holder  or  mains  will  often  cause  a 
seemingly  disproportionate  loss  of  candlepower,  and  this  can 
generally  be  traced  to  improper  fixation  of  the  oil  gas. 

With  oil  and  acetylene  gases  the  candlepower  is  usually  so  high 
that  it  seems  needless  to  consider  any  possible  causes  of  loss  in 
that  respect,  save  as  they  are  related  to  the  calorific  value,  so  that 
the  subject  will  be  dismissed  for  the  present  with  a  few  words. 
With  acetylene  the  principal  cause  of  diminution  in  candlepower 
is  overheating  in  the  generator;  this  frequently  happens  in  the 
water-to-carbide  type  of  machines  and  results  in  polymerization  of 
the  acetylene  and  formation  of  benzene,  styrolene,  etc.  Not  only 
is  the  yield  thus  reduced  and  the  candlepower  lowered,  but  the 
tarry  products  formed  by  overheating  cause  carbonization  of  the 
burners,  which  become  choked  and  smoky.  The  evidence  of 
such  overheating  will  also  be  found  on  the  lime  left  after  genera- 
tion, for  whereas  it  should  be  comparatively  white,  if  overheating 
has  occurred,  it  will  be  of  a  dirty  yellow  or  brown  color  and  may 
contain  deposits  of  tarry  matter. 

In  the  case  of  oil  gases  it  is  a  not  infrequent  practice  to  mix 
them  with  air.  This  in  itself  is  perfectly  proper  since  it  serves 


INTERPRETATION   OF   RESULTS  ?/ 

a  useful  purpose  in  diluting  a  gas  which  is  too  rich  in  ordinary 
burners  and  in  supplying  oxygen  to  assist  in  the  combustion  of 
the  heavy  hydrocarbons;  but  it  is  always  possible  that  more  air 
will  be  admitted  than  can  be  handled  by  the  gas,  in  which  case 
the  candlepower  will  of  course  drop  to  a  marked  extent.  The 
writer  has  tested  a  gas  of  this  type,  which  under  ordinary  circum- 
stances would  be  of  about  35  candlepower,  and  which  in  this  case 
had  dropped  to  16  candlepower,  presumably  for  the  above  reason. 

It  may  be  interesting  to  note  some  of  the  results  which  may  be 
expected,  or  which  may  be  unexpectedly  found  in  the  determina- 
tion of  the  candlepower  of  the  various  gases.  Of  necessity  these 
will  depend  considerably  on  the  locality  and  the  presence  or 
absence  of  governmental  regulations,  so  that  no  single  set  figure 
can  be  given  in  any  case. 

In  the  United  States  a  good  unenriched  coal  gas,  with  a  yield 
of  4.75  to  4.90  feet  per  pound  should  run  from  14  to  16  candle- 
power.1  If  only  the  best  gas  from  the  run  is  accepted,  the  yield 
will  be  much  lower  but  the  candlepower  ma'y  reach  as  high  as 
19  or  20.1  This  is  not  an  economical  method  of  manufacture, 
and  there  is  positive  harm  in  so  high  a  candlepower  for  coal  gas, 
since  mantles  and  ceilings  will  be  quickly  disfigured  by  the  smoke 
or  by  deposited  carbon.  The  writer  has  seen  a  coal  gas  of  only 
8  candlepower  1  supplied  for  municipal  use  in  open  burners,  and 
has  also  in  mind  a  city  where  the  candlepower  is  generally  below 
13  51  but  such  gases  are  not  to  be  commended  and  there  is 
clearly  some  serious  error  in  the  management  of  the  plants. 

If  properly  enriched,  coal  gas  can  easily  be  made  the  year 
round  of  16  to  17  candlepower,1  and  this  is  an  excellent  quality 
of  gas,  considered  both  from  the  side  of  its  heating  and  of  its  illu- 
minating value.  Whether  such  a  gas  is  the  most  economical  for 
the  consumer,  when  the  cost  of  enrichment  is  considered,  is  a 
different  question,  and  it  is  more  than  probable  that  if  the  price 
of  the  gas  were  reduced  to  correspond  with  the  decrease  in  candle- 
power,  a  lower  figure  for  the  latter  would  be  more  satisfactory  to 
all  concerned,  particularly  when  it  is  remembered  that  the  greater 

1  Taken  with  burner  best  adapted  to  gas  (Metropolitan  No.  2  excepted). 


7#  GAS   AND   GAS   METERS 

part  of  the  gas  used  to-day  is  burned  in  appliances  where  its 
calorific  value  is  of  far  more  importance  than  its  illuminating 
power. 

A  blue  or  unenriched  water  gas,  as  its  name  implies,  burns  with 
a  blue  flame  and  thus  is  of  no  value  for  lighting  if  used  in  open 
burners.  A  good  carburetted  water  gas,  as  made  in  this  country, 
yields  from  20  to  28  candlepower.  The  general  practice  to-day  is 
to  maintain  this  figure  as  near  20  as  possible,  save  where  local 
regulations  compel  different  results.  As  examples  of  the  extremes, 
however,  the  writer  has  tested  a  water  gas  of  less  than  9  candle- 
power  and  another  of  28  candlepower,  both  supplied  for  use  in 
open  burners.  The  former  is  undoubtedly  evidence  of  faulty 
manufacture,  while  the  latter  is  far  richer  than  is  desirable,  not 
only  from  the  standpoint  of  economy,  but  also  because  it  is  a 
menace  to  mantles  and  ceilings. 

A  mixed  gas,  or  a  mixture  of  coal  and  water  gas,  may  naturally 
be  of  almost  any  candlepower,  dependent  upon  the  value  of  the 
components  of  the  ^mixture  and  their  proportion.  As  a  rule,  the 
candlepower  of  mixed  gas  is  from  17  to  20.  The  Rochester  Rail- 
way &  Light  Company,  of  Rochester,  N.  Y.,  voluntarily  offered 
to  maintain  its  gas  at  20  candlepower,  and  almost  without  excep- 
tion has  lived  up  to  this  agreement,  thus  showing  the  possibilities 
of  making  a  mixed  gas  of  that  candlepower  with  a  reasonable 
profit. 

A  straight  oil  gas,  well  made,  will  give  a  candlepower  of  45  to 
60;  gasolene,  12  to  17;  an  oil-air  gas  should  be  from  30  to  35,  and 
acetylene  from  170  to  200  candlepower.  For  the  last-mentioned 
gas  many  claims  are  made  for  illuminating  values  ranging  from 
200  to  240  candlepower,  but  it  is  doubtful  if  such  figures  are  ever 
reached  in  practical  work.  Certainly  they  have  never  been 
approached  in  the  tests  made  by  inspectors  in  the  states  of  New 
York  and  Massachusetts. 

The  candlepower  of  natural  gas  will  vary  greatly  according  to 
the  field  from  which  it  is  drawn,  and  any  result  from  4  to  16  may 
be  expected. 

In  Australia  the  standard   illuminating  power  in   Melbourne 


INTERPRETATION   OF  RESULTS  79 

and  Perth  is  15;  at  Adelaide,  17.5,  and  at  Ballarat,  18.  In  Bom- 
bay, India,  it  is  14  candlepower;  in  Tokio,  Japan,  the  company 
supplies  i6-candle  coal  and  i8-candle  water  gas.  Colombo  has 
lo-candle  gas,  and  the  same  is  true  of  Berlin.  Scotland  has 
always  maintained  an  unnecessarily  high  illuminating  value;  in 
January,  1907,  there  were  only  two  authorized  gas  undertakings 
supplying  under  2o-candlepower  gas.  This  has  not  been  due, 
however,  to  legal  restrictions,  for  out  of  the  50  authorized  concerns 
supplying  gas,  22  have  their  required  illuminating  power  pre- 
scribed as  14,  yet  the  gas  supplied  by  them  severally  is  at  a  figure 
between  20  and  29  candles.1  In  England  the  tendency  of  late 
years  has  been  to  reduce  the  requirements  and  to  increase  the 
accuracy  and  efficiency  of  the  instruments  employed;  so  that  in 
London  to-day  there  are  two  standards  of  14  and  16  candlepower 
respectively,  and  the  tests  are  made  with  the  Carpenter  burner, 
which  gives  about  2  candlepower  higher  results  than  are  obtained 
with  the  Suggs  Argand  burner. 

Such  being  the  figures  at  which  gas  is  supplied  in  various  parts 
of  the  world,  a  moment's  attention  may  well  be  given  to  some  of  the 
legal  requirements  regarding  candlepower  in  different  places.  In 
England,  the  birthplace  and  training  school  of  the  gas  industry,  the 
first  act  for  the  regulation  of  gas  companies  was  passed  in  1833. 
This  was  entitled  the  Lighting  and  Watching  Act,  but  contained  no 
mention  of  illuminating  value.  In  1847,  another  act  concerning 
gas  was  passed,  and  still  there  was  no  mention  of  candlepower 
requirements.  By  the  Great  Central  Gas  Act  of  1850,  however, 
wax  candles,  weighing  six  to  the  pound  and  burning  at  the  rate  of 
120  grains  per  hour,  were  specified  as  standards  for  photometric 
work.  From  this  time  on  there  has  always  been  governmental 
regulation  of  the  gas  industry,  and  the  standard  of  candlepower 
has  been  set  at  16,  until  1905,  when  by  the  London  Gas  Act  it  was 
reduced  to  14  for  the  South  Metropolitan  and  Commercial  Gas 
Companies. 

In  Berlin  and  Colombo,  as  has  been  stated,  the  law  requires 
only  10  candlepower;  Dublin,  Ireland,  and  Ontario,  Canada,  have 

1  Journal  of  Gas  Lighting,  January  15,  1907. 


80  GAS   AND    GAS    METERS 

16  candlepower,  and  in  general  it  may  be  said  that  the  require- 
ments are  much  less  stringent  abroad  than  in  this  country. 

Turning  now  to  the  United  States,  the  pioneer  in  matters  of  gas 
regulation  is  Massachusetts,  where  a  state  inspector  has  been 
steadily  employed  for  over  45  years.  The  standard  for  candlepower 
in  this  state  started  at  the  surprising  figure  of  12.  This  was  after- 
wards raised  to  15,  and  in  March,  1892,  on  the  recommendation  of 
the  state  inspector,  it  was  again  raised,  this  time  to  16,  at  which 
figure  it  has  continued  ever  since. 

In  the  State  of  New  York  various  standards  have  been  set;  thus 
by  an  act  of  the  Legislature  of  1905  the  gas  in  New  York  City  was 
required  to  be  of  at  least  22  candlepower.  In  1907,  an  act  to  set  the 
same  standard  in  Albany  was  enacted,  but  this  was  superseded 
during  the  same  year  by  the  Second-Class  Cities  Law,  which 
demands  that  the  minimum  candlepower  of  coal  gas  shall  be  16, 
of  water  gas,  20,  and  of  a  mixture  of  coal  and  water  gas,  18.  These 
last  are  likewise  the  figures  set  for  all  coal  and  water  gas  plants 
throughout  the  state  by  an  order  of  the  former  Commission  of  Gas 
and  Electricity,  issued  in  1907,  and  by  a  separate  act  for  the  city  of 
Syracuse,  known  as  the  Hammond  Bill. 

In  Auburn  an  agreement  between  the  gas  company  and  the  city 
calls  for  1 8  candlepower;  in  Rochester  the  company  has  agreed  to 
furnish  20  candlepower,  and  in  Buffalo,  by  a  contract  recently 
expired,  the  candlepower  was  to  be  maintained  at  18.  The  gas 
company  at  Plattsburgh  is  likewise  under  agreement  to  furnish 
i8-candle  gas. 

In  Wisconsin  the  subject  of  candlepower  requirements  has 
received  careful  consideration,  and  the  Board  of  Railroad  Commis- 
sioners, which  has  supervision  of  the  gas  companies,  has  decided 
that  it  is  not  desirable  to  set  any  standard  whatever  for  candle- 
power,  for  the  reason  that  most  of  the  gas  used  in  the  state  is 
employed  in  such  a  manner  that  its  heating  value  and  not  its  illumi- 
nating power  is  the  vital  point  to  be  considered. 

In  the  District  of  Columbia  the  standard  is  22  candlepower,  and 
even  though  at  least  one  of  the  companies  there  manufactures 
largely  coal  gas,  the  law  is  generally  complied  with.  Various  cities 


INTERPRETATION   OF   RESULTS  8 1 

throughout  the  country  have  standards  of  their  own,  and  in  general 
public  opinion  has  prevented  these  from  falling  below  16,  but  it  is  to 
be  expected  that  with  the  increasing  cost  of  manufacture,  the  diffi- 
culty in  securing  good  coal  and  enriching  materials  at  reasonable 
prices,  and  the  tendency  to  abolish  the  flat-flame  burner,  these 
candlepower  requirements  will  in  the  near  future  be  done  away 
with  and  a  standard  of  heating  value  substituted  therefor. 


PART  II. 

CHEMICAL   TESTS. 


PART  II. 

CHEMICAL    TESTS. 


CHAPTER  I. 
CARBONIC  ACID  AND  SULPHURETTED  HYDROGEN. 

THE  chemical  tests  which  may  be  profitably  employed  in  connec- 
tion with  the  manufacture  of  gas  are  very  numerous  and  would  of 
themselves  fill  a  large  volume.  As  the  purpose  of  this  work,  how- 
ever, is  to  treat  of  the  finished  product  only,  no  mention  will  be 
made  of  the  analysis  of  coal,  oil,  tar,  coke,  carbide,  benzole,  etc. 
Many  thorough  studies  have  been  made  and  published  regarding 
each  of  these,  and  it  is  believed  that  these  books  devoted  to  a  single 
line  of  thought  should  serve  as  the  basis  for  analytical  work  rather 
than  such  hasty  and  incomplete  discussion  of  the  subjects  as  would 
be  necessary  in  the  limited  space  of  this  work.  Neither  is  it  feasible 
nor  desirable  to  attempt  to  give  all  of  the  methods  which  have  been 
proposed  for  the  estimation  of  the  various  impurities,  such  as  sul- 
phur, ammonia,  etc.,  for  many  of  these  have  proved  themselves  to 
be  inaccurate  and  others  are  not  adapted  to  a  gas  works  laboratory, 
being  either  too  tedious,  unnecessarily  exact,  or  requiring  peculiar 
and  costly  apparatus. 

While  quoting,  therefore,  one  or  two  methods  for  the  determi- 
nation of  each  substance,  the  intention  will  be  to  lay  more  stress 
on  the  principles  underlying  each  process  and  to  give  a  detailed 
account  of  the  procedure^  reactions,  and  calculations  involved  in 
one  reliable,  rapid,  and  accurate  method.  Consideration  will  be 
given  to  the  following  impurities,  all  of  which  are  generally  present, 
to  a  greater  or  less  extent,  in  the  gas  as  it  is  delivered  to  the  holder: 
carbonic  acid,  sulphuretted  hydrogen,  total  sulphur,  carbon 

85 


86  GAS   AND    GAS   METERS 

bisulphide,  ammonia,  naphthalene,  cyanogen,  arsenic,  silicon,  and 
phosphorus.  The  last  three  are  as  a  rule  found  only  in  acetylene, 
while  the  latter  gas  may  also  contain  all  the  rest  of  the  impurities 
mentioned  with  the  possible  exception  of  naphthalene.  Carbon 
monoxide  is  not  mentioned  in  this  list  for  two  reasons:  first,  it  is 
a  normal  and  necessary  constituent  of  water  gas  and  so  cannot  be 
considered  as  an  impurity;  second,  the  methods  for  its  determi- 
nation will  be  given  so  fully  in  a  succeeding  chapter  that  they  need 
not  be  inserted  here. 

Carbonic  Acid.  The  importance  of  this  compound  has  already 
been  dwelt  upon  in  connection  with  the  candlepower  of  water  gas. 
In  a  purified  coal  gas  it  should  not  be  present  to  the  extent  of  over 
i  to  2  per  cent;  in  carburetted  water  gas  the  limit  may  be  set  at 
3  per  cent,  while  in  gasolene  and  acetylene  gases  the  amount 
present  is  almost  always  so  small  as  to  be  unimportant.  The 
general  procedure  in  all  processes  for  the  determination  of  car- 
bonic acid  is  to  bring  a  measured  quantity  of  the  gas  to  be  tested 
in  contact  with  a  solution  of  caustic  potash,  caustic  soda  or  barium 
hydrate  and  after  shaking  the  reagent  and  gas  together  for  a  short 
time  to  either  measure  the  gas  remaining  or  to  ascertain  the  amount 
of  alkali  unacted  on.  The  reactions  which  take  place  are  as 
follows : 

KOH  +  H2CO3    -  KHCO3  +  H2O2 
KOH  +  KHC03  =  K2C03  +  H2O. 

The  symbol  usually  given  for  carbonic  acid  is  CO2.  Strictly 
speaking  this  is  incorrect,  as  CO2  represents  the  anhydride  of 
carbonic  acid,  that  is,  the  latter  with  one  molecule  of  water  ex- 
tracted. The  correct  symbol  then  is  H2CO3,  or  it  may  be  written 

^0  =  0    which    is    called    the    graphic    symbol.     This 

compound  H2CO3  is  assumed  to  be  formed  whenever  the  anhy- 
dride CO2,  which  is  gaseous,  is  dissolved  in  water;  and  while  it 
has  never  been  isolated,  it  is  reasonably  certain  that  it  is  the  form 
which  enters  into  reactions. 

The  first  effect  of  the  caustic  potash  on  this  substance  is  to 
form  potassium  bicarbonate  (KHCO3)  and  to  liberate  one  mole- 


CARBONIC  ACID  AND  SULPHURETTED  HYDROGEN    8/ 

cule  of  water.  The  reaction  does  not,  however,  end  here.  The 
potassium  bicarbonate  reacts  with  more  of  the  caustic  potash  to 
form  neutral  potassium  carbonate,  K2CO3,  and  another  molecule 
of  water  is  thrown  off.  As  the  affinity  of  carbonic  acid  for  caustic 
potash  is  very  great,  all  of  the  former  in  the  gaseous  mixture  is 
speedily  extracted  and  the  volume  of  the  gas  is  of  course  lessened 
by  the  volume  of  carbonic  acid  which  it  has  lost.  Now  by  dividing 
the  loss  in  volume  by  the  original  volume  the  percentage  of  car- 
bonic acid  is  easily  obtained.  Thus,  if  a  gaseous  mixture  of  100  c.c. 
was  subjected  to  treatment  with  caustic  potash  and  10  c.c.  were 
lost  by  such  action,  the  carbonic  acid  evidently  formed  xA  of  the 
mixture,  or  10  per  cent. 

Unfortunately  carbonic  acid  is  not  the  only  body  present  in 
illuminating  gas  which  reacts  with  caustic  potash.  If  a  gas  con- 
taining both  carbonic  acid  and  sulphuretted  hydrogen  be  sub- 
jected to  the  action  of  caustic  potash,  both  of  the  ingredients 
mentioned  will  be  absorbed,  the  reaction  with  the  sulphuretted 
hydrogen  being  exactly  similar  to  the  one  already  shown  for  car- 
bonic acid.  Thus, 

KOH  +  H2S    =KHS  +  H2O 
KOH  +  KHS=K2S  +  H20. 

Now  in  cases  where  sulphuretted  hydrogen  is  present  it  will 
readily  be  seen  that  we  cannot  simply  shake  the  gas  with  caustic 
potash,  note  the  diminution  in  volume  and  call  that  loss  the  amount 
of  carbonic  acid  present;  for  the  loss  also  includes  the  sulphuretted 
hydrogen.  It  is  therefore  necessary  to  remove  the  latter  before 
making  the  test  for  carbonic  acid,  and  this  may  be  done  by  passing 
.the  gas  through  a  solution  which  has  the  power  of  absorbing  the 
sulphuretted  hydrogen  and  not  the  carbonic  acid.  Such  a  solution 
may  contain  copper  sulphate,  cupric  phosphate,  cadmium  chloride, 
manganese  binoxide  with  phosphoric  acid,  etc.  The  last  named 
was  recommended  by  Bunsen  and  is  not  dissolved,  but  the  man- 
ganese binoxide  is  made  into  the  form  of  a  ball  and  soaked  several 
times  in  syrupy  phosphoric  acid.  It  is  also  possible  to  remove  the 
sulphuretted  hydrogen  by  means  of  a  small  oxide  purifier,  and  in 


88  GAS   AND   GAS    METERS 

works  use  this  would  seem  to  be  the  most  satisfactory  plan. 
Ammonia  must  also  be  removed,  or  in  the  volumetric  processes 
it  may  increase  the  alkalinity  of  the  solution  and  thus  render  the 
carbonic  acid  results  too  low.  As  a  rule,  however,  ammonia  and 
free  carbonic  acid  do  not  exist  long  in  the  same  solution. 

And  now  two  general  methods  are  available  for  the  determina- 
tion of  the  carbonic  acid,  the  gravimetric  and  the  volumetric.  By 
the  first,  a  measured  volume  of  gas  is  bubbled  slowly  through  a 
solution  of  barium  hydrate,  the  precipitate  of  barium  carbonate 
which  forms  is  collected  on  a  filter,  washed,  dried,  ignited,  and 
weighed.  From  the  weight  of  barium  carbonate  formed  and  the 
amount  of  gas  used,  the  percentage  of  carbonic  acid  can  be  readily 
obtained.  For  example,  if  one  cubic  foot  of  gas  was  passed 
through  the  solution  and  the  barium  carbonate  formed  weighed 
4.2864  grams,  the  calculation  would  proceed  thus: 

BaCO3  :  CO2  :  :  4.2864  :  x. 
197         44 

x  =  0.9574  gram  of  carbonic  acid  from  i  cubic  foot  of  gas. 
To  change  this  to  grains  per  hundred  cubic  feet  it  is  only 
necessary  to  multiply  by  100  X  15.432,  since  i  gram  equals 
15.432  grains.  So  0.9574  X  100  X  15.432  =  1477  grains  per 
hundred  cubic  feet.  If  it  is  desired  to  express  the  result  in  per 
cent,  i  grain  CO2  =  0.001231  cubic  foot.  Then  1477  grains 
=  1477  X  0.001231  =  1.82  cubic  feet  CO2  per  100  cubic  feet 
of  gas,  or  1.82  per  cent  by  volume.  These  calculations  are 
of  course  based  on  the  assumption  that  the  volume  of  gas  used, 
i  cubic  foot,  has  been  corrected  for  temperature  and  pressure. 
The  only  solution  needed  for  this  method  is  one  of  barium  hydrate, 
which  is  made  by  dissolving  50  grams  of  pure  Ba(OH)2«8H2O 
in  one  liter  of  distilled  water.  This  solution  should  be  protected 
from  contact  with  the  air  with  the  especial  view  of  excluding 
carbonic  acid.  The  method  is  fairly  accurate,  but  cumbersome 
and  not  as  rapid  as  the  volumetric  processes. 

Another  gravimetric  method  consists  in  passing  the  gas  through 
a  series  of  U  tubes  containing  soda-lime,  which  has  the  power  of 


CARBONIC   ACID   AND    SULPHURETTED   HYDROGEN         89 

absorbing  carbonic  acid.  By  weighing  these  tubes  before  and 
after  the  passage  of  the  gas,  the  weight  of  carbonic  acid  in  a  given 
volume  of  gas  is  found  directly. 

All  of  the  volumetric  methods  are  essentially  the  same:  the 
carbonic  acid  in  a  known  quantity  of  gas  is  absorbed  in  an  excess 
of  a  solution  of  caustic  potash  or  barium  hydrate  of  known  strength 
and  the  amount  of  alkali  unacted  on  by  the  carbonic  acid  is  deter- 
mined by  titration  with  a  standard  acid  solution.  The  method  of 
procedure  may  be  as  follows :  measure  from  a  burette  three  portions 
of  20  c.c.  each  of  the  standard  alkali  and  place  one  portion  in  each 
of  three  bulbs,  bottles,  or  other  receptacles  connected  together. 
Connect  the  inlet  of  the  series  with  the  source  of  the  gas  to  be 
tested  and  the  outlet  to  a  fourth  bulb  containing  caustic  potash, 
which  in  turn  is  connected  with  a  meter.  The  object  of  the  fourth 
bulb  is  to  exclude  air  from  the  apparatus. 

Now  cause  a  known  amount  of  gas  to  bubble  through  the  potash, 
empty  the  contents  of  the  first  three  bulbs  into  a  flask,  add  two 
drops  of  methyl  orange  or  of  cochineal  and  run  in  the  standard 
acid  from  a  burette  until  the  color  just  changes  from  a  yellow  (in 
the  case  of  methyl  orange)  or  a  violet  (in  the  case  of  cochineal) 
to  a  pink  or  yellow  respectively.  The  methyl  orange  is  the  better 
indicator,  although  it  takes  a  little  more  practice  to  judge  of  the 
end-point  accurately  than  is  the  case  with  cochineal. 

The  solutions  necessary  for  this  method  are  prepared  as  follows : 

Cochineal:  grind  three  grams  of  whole  cochineal  in  250  c.c.  of  a 
mixture  of  3  to  4  volumes  of  water  and  i  volume  of  alcohol  and 
decant  the  clear  solution.1 

Methyl  orange:  the  powder  may  be  purchased  under  the  name 
of  Poirriers  orange  III,  Tropaeolin  D  or  Helianthine;  one  gram 
dissolved  in  a  liter  of  water  is  a  convenient  strength. 

Standard  solution  of  caustic  potash:  this  substance  can  now  be 
obtained  in  a  state  of  great  purity;  the  solution  should  contain 
about  12  grams  to  the  liter,  and  it  is  only  necessary  to  weigh  out 
this  amount  and  dissolve  it  in  one  liter  of  distilled  water.  The 
exact  weight  of  the  caustic  potash  used  is  not  required,  since  the 

Cohn,  Indicators  and  Test  Papers.   * 


90  GAS   AND    GAS   METERS 

strength  of  the  solution  must  later  be  determined  in  any  case 
by  titration  with  standard  acid. 

Tenth  normal  hydrochloric  acid:  the  chemically  pure  hydro- 
chloric acid  of  commerce,  of  specific  gravity  i.io,  contains  20.2  per 
cent  by  weight  of  hydrochloric  acid.  Now  a  tenth  normal  solution 
of  this  acid  contains  3.645  grams  of  the  gas  in  each  liter.  There- 
fore, 3.645X100^-20.2  or  approximately  18.1  c.c.  of  hydrochloric 
acid  (sp.  gr.  i.i)  diluted  to  one  liter  will  give  a  solution  which  is 
approximately  tenth  normal. 

Having  made  the  reagents  it  is  now  necessary  to  determine  their 
exact  strength.  To  standardize  the  hydrochloric  acid,  first  make 
a  tenth  normal  solution  of  sodium  carbonate  by  dissolving  exactly 
5.3  grams  of  the  pure  dry  salt  in  one  liter  of  water.  If  a  guaranteed 
quality  of  this  substance  cannot  be  purchased,  it  may  be  prepared 
by  igniting  a  platinum  crucible  half  full  of  very  pure  sodium 
bicarbonate  at  a  dull  red  heat  for  an  hour  followed  by  cooling  in  a 
desiccator.  Now  fill  a  burette  with  the  standard  carbonate  solu- 
tion and  another  with  the  acid  to  be  tested.  Run  25  c.c.  of  the 
former  into  a  small  flask,  add  two  or  three  drops  of  methyl  orange 
and  then  add  acid  from  the  second  burette  with  continual  stirring 
or  shaking,  until  the  yellow  color  of  the  solution  just  changes  to  a 
faint  pink.  Read  the  acid  burette  and  repeat  the  titration  with 
fresh  portions  of  alkali  and  acid  until  check  results  have  been 
secured.  The  calculation  is  then  made  as  follows: 

Assume  25  c.c.  N/io  sodium  carbonate  =  27.2  c.c.  hydrochloric 
acid,  i  c.c.  hydrochloric  acid  =  0.919  c.c.  N/io  sodium  carbonate, 
but  since  the  sodium  carbonate  =  5.3  grams  to  the  liter,  i  c.c. 
hydrochloric  acid  =  (0.919  X  0.0053),  or  0.00487  gram  sodium 
carbonate, 

2  HC1  :  Na2CO3  :  :  x  :  0.00487. 

73  106 

x  =  0.00335,  therefore  i  c.c.  of  the  hydrochloric  acid  contains 
0.00335  gram  of  that  gas.  This  result  could  have  been  obtained 
without  any  of  this  figuring  by  remembering  the  properties  of 
normal  solutions.  Thus,  since  the  sodium  carbonate  is  N/io 
and  i  c.c.  of  hydrochloric  acid  =  0.919  c.c.  sodium  carbonate, 


CARBONIC    ACID   AND   SULPHURETTED   HYDROGEN         91 

the  hydrochloric  acid  must  be  919/1000  of  N/io.  A  N/io  solu- 
tion of  hydrochloric  acid  contains  0.00365  gram  hydrochloric 
acid  per  c.c.,  so  the  solution  in  question  would  contain  0.00365 
X  0.919,  or  0.00335  gram  of  hydrochloric  acid  per  c.c. 

Having  obtained  this  factor,  it  is  now  easy  to  ascertain  the 
strength  of  the  caustic  potash.  The  titration  of  this  against  the 
acid  proceeds  exactly  as  described  above  for  the  standardization 
of  the  acid.  Let  us  assume  that  25  c.c.  of  acid  require  13.4  c.c. 
of  caustic  potash.  Then  i  c.c.  or  0.00335  gram  hydrochloric 
acid  =  0.536  c.c.  caustic  potash. 

KOH  :  HC1  :  :  x  :  0.00335. 

56        36-5 

x  =  0.00514.  If  0.536  c.c.  caustic  potash  =  0.00514  gram, 
i  c.c.  contains  0.00959  gram  of  caustic  potash.  Or,  using  nor- 
mal solutions,  the  caustic  potash  is  25/13.4  X  0.0919  normal. 
One  c.c.  of  normal  caustic  potash  contains  0.056  gram. 
25  X  0.0919  X  0.056  -r-  13.4  =  0.00959  gram  of  caustic  potash 
per  c.c.  of  solution.  It  is  now  convenient  to  transform  this  result 
into  such  a  form  that  it  will  be  available  for  use  in  each  determi- 
nation with  as  little  calculation  as  possible.  To  do  this  it  is 
only  necessary  to  find  the  value  of  i  c.c.  of  the  caustic  potash  in 
terms  of  carbonic  acid. 

2  KOH  :  CO2  :  :  0.00959  :  x. 
112         44 

x  =  0.00377  gram  of  carbonic  acid  which  will  be  neutralized  by 
i  c.c.  of  the  caustic  potash. 

To  consider  an  actual  determination  with  the  above  solutions: 
60  c.c.  of  caustic  potash  were  used  in  the  bulbs;  i  cubic  foot  of 
gas  was  passed  through,  and  it  then  required  90  c.c.  of  the  hydro- 
chloric acid  to  neutralize  the  remaining  potash. 

90  c.c.  HC1  =  (90  X  0.536)  c.c.  KOH  =  48.24  c.c. 
60  —  48.24  =  11.76  c.c.  KOH  used  up  by  the  CO2. 
11.76  X  0.00377  =  0.0443  gram  CO2  in  i  cubic  foot  of  gas, 
or  0.0443  X  zoo  X  15.43  =  68.35  grains  CO2  per   100  cubic 
feet  of  gas. 


92  GAS   AND    GAS   METERS 

It  may  have  been  noticed  that  the  gas  is  measured  after  it  has 
passed  through  the  potash  solution  and  not  before.  This  is  done 
for  the  reason  that  the  water  in  a  wet  meter  will  dissolve  car- 
bonic acid  and  under  certain  circumstances  give  it  up  again  to  a 
passing  current  of  gas;  consequently  the  experimenter  would 
never  be  certain  of  his  results.  The  volume  of  the  gas  as  deter- 
mined after  passing  the  caustic  potash  bulbs  is  of  course  less 
than  the  original  volume  by  the  amount  of  carbonic  acid  absorbed, 
and  if  great  accuracy  is  desired,  a  correction  must  be  made  for 
this.  In  the  example  cited,  however,  the  carbonic  acid  absorbed 
is  only  equal  to  0.0008  cubic  feet,  so  that  in  this  case  the  error  is 
decidedly  negligible. 

Hempel  recommends,  for  the  determination  of  small  quan- 
tities of  carbonic  acid,  a  solution  of  barium  hydrate  and  titra- 
tion  with  oxalic  acid.  The  objection  to  oxalic  acid  in  this  con- 
nection is  that  it  is  not  stable  and  must  be  carefully  standardized 
before  each  determination;  while  a  N/io  solution  of  hydro- 
chloric acid  will  retain  its  strength  almost  indefinitely.  The 
barium  hydrate  will  work  perfectly  well  if  it  is  kept  without 
access  of  air;  but  if  it  comes  in  contact  with  carbonic  acid  a  tur- 
bidity of  barium  carbonate  will  form,  and  the  solution  must  be 
filtered  before  using. 

Hempel  also  gives  a  very  excellent  method  for  the  rapid  and 
accurate  estimation  of  carbonic  acid  in  illuminating  gas  which  is 
so  well  described  that  the  author's  words  are  quoted  verbatim: 
"The  carbonic  acid  can  be  determined  with  great  exactness  with 
the  apparatus  devised  by  Riidorff.  This  consists  of  a  three- 
necked  bottle  A  (Fig.  14);  in  one  neck  the  manometer  B  filled 
with  a  solution  of  indigo  is  inserted;  in  the  second  neck  the  glass 
stopcock  pipette  C  graduated  in  tenths;  and  in  the  third  neck 
either  a  single  glass  stopcock  or  a  double  bore  stopper  carrying 
two  tubes,  one  of  which  reaches  to  the  bottom  of  the  bottle,  while 
the  other  ends  just  below  the  stopper. 

"The  exact  contents  of  the  bottle  must  be  known.  In  making 
the  determination  illuminating  gas  is  led  into  the  bottle  until  all 
of  the  air  is  driven  out,  the  lighter  gas  being  introduced  at  the 


CARBONIC   ACID    AND    SULPHURETTED    HYDROGEN 


93 


top  of  the  bottle  and  the  heavier  air  passing  out  below.  The 
stopcocks  are  now  closed,  and  the  manometer  is  brought  to  zero 
by  carefully  allowing  some  of  the  gas  which  is  in  the  bottle,  and 
which  is  under  pressure,  to  escape.  If  now  a  solution  of  caustic 
potash  be  allowed  to  drop  from  the  pipette  into  the  bottle,  the 
carbonic  acid  will  be  absorbed.  The  volume  of  the  carbonic 
acid  present  can  be  read  off  directly  from  the  pipette,  if,  after  the 


Fig.  14.     Riidorff' s  Apparatus  for  Carbonic  Acid. 

absorption,  the  manometer  is  again  brought  to  zero  by  admitting 
more  caustic  potash. 

"In  this  determination  the  gas  must,  of  course,  be  free  from 
sulphuretted  hydrogen.  If  this  is  not  the  case,  the  gas  is  passed 
through  manganese  binoxide  before  entering  the  apparatus.  To 
avoid  changes  of  temperature  it  is  advisable  to  place  the  appara- 
tus in  a  vessel  of  water  during  the  experiment. 

"It  is  self  evident  that  the  apparatus  in  this  form  is  influenced 
by  changes  of  temperature  and  pressure  of  the  atmosphere.  It 
can  be  made  independent  of  these  by  attaching  a  Pettersson 


94  GAS    AND    GAS   METERS 

compensating  tube  to  the  manometer  as  in  Fig.  14."     This  is  a 
most  excellent  method  and  highly  to  be  recommended. 

Only  one  other  method  need  be  mentioned,  and  that  because  of 
its  difference  in  character  from  all  of  those  hitherto  described. 
This  is  by  use  of  the  Harcourt  apparatus,  which  consists  in  its 
essential  features  of  two  glass  cylinders  (Fig.  16),  a  large  tank  or 
aspirator  and  a  graduated  vessel.  One  of  the  cylinders  contains 
a  liquid  in  which  is  suspended  a  definite  amount  of  barium  car- 
bonate; the  other  is  charged  with  a  saturated  solution  of  barium 
hydrate.  By  means  of  the  aspirator,  gas  is  sucked  through  the 
barium  hydrate  until  the  turbidity  in  that  cylinder  is  equal  to 
that  in  the  one  containing  the  known  amount  of  barium  carbonate. 
The  water  running  from  the  aspirator  is  caught  in  the  graduate, 
and  thus  the  quantity  of  gas  necessary  to  precipitate  a  known 
weight  of  barium  carbonate  is  ascertained.  The  method  is  rapid, 
but  not  accurate;  the  principle  involved  has  been  tested  many 
times  in  connection  with  water  analysis,  and  no  method  founded 
on  it  has  as  yet  proved  satisfactory.  It  will  serve,  however,  as  a 
convenient  means  of  securing  approximate  results. 

Thus  far  all  of  the  methods  mentioned  have  been  quantitative; 
if  a  qualitative  test  for  carbonic  acid  is  desired,  it  is  only  necessary 
to  allow  some  of  the  gas  to  bubble  through  a  clear  solution  of 
barium  hydrate,  when,  if  carbonic  acid  be  present,  the  liquid 
takes  on  a  milky  appearance. 

An  apparatus  for  the  continuous  determination  of  carbonic  acid 
is  manufactured  by  Alexander  Wright  &  Co.,  under  the  name  of 
Simmance  &  Abady's  Patent  Automatic  Combustion  Recorder 
(Fig.  15).  With  this  instrument  a  charge  of  gas  is  bubbled 
through  a  caustic  potash  solution  every  so  often,  and  the  unab- 
sorbed  gas  is  passed  on  to  a  small  bell,  the  rise  of  which  indicates 
on  a  scale  the  percentage  of  the  carbonic  acid.  A  mark  is  also 
made  at  the  same  time  on  a  chart  showing  whether  the  carbonic 
acid  be  high  or  low;  this  chart  will  furnish  a  continuous  record 
for  60  days.  The  cost  of  the  instrument  is  $250,  and  while  doubt- 
less a  handy  thing  to  possess,  it  is  primarily  intended  as  an  aid  to 
the  securing  of  proper  combustion  of  coal  in  boilers,  etc.,  and 


CARBONIC   ACID  AND   SULPHURETTED    HYDROGEN         95 

would  seem  to  be  more  of  a  luxury  than  a  necessity  for  a  gas 
works. 

Acetylene  rarely  if  ever  contains  carbonic  acid;  if  it  be  present, 
it  is  in  such  small  amounts  as  to  be  unworthy  of  attention.     In 


Fig.  15.     Recording  Apparatus  for  Carbonic  Acid. 

natural  gas,  the  carbonic  acid  content  is  generally  under  i  per 
cent;  out  of  42  analyses  before  the  writer,  but  one  shows  over 
i  per  cent  carbonic  acid.  In  crude  coal  gas  after  condensation 
but  prior  to  washing  the  carbonic  acid  will  be  from  i.i  to  1.8  per 
cent  by  volume,  or  980  to  1470  grains  per  100  cubic  feet;  after 
passing  the  scrubbers  it  is  reduced  to  700  to  noo  grains  per  100 


96  GAS   AND    GAS    METERS 

cubic  feet.  Out  of  142  analyses  of  purified  coal  gas  made  by  the 
state  inspectors  of  Massachusetts  between  1883  and  1906,  only  18 
showed  over  1.5  per  cent  of  carbonic  acid,  and  most  of  them  were 
far  below  this  figure.  With  water  gas,  as  has  been  stated,  the 
percentage  of  carbonic  acid  will  vary  greatly  according  to  the  con- 
ditions of  generation.  The  unpurified  gas  should  contain  a  little 
less  than  3  per  cent  by  volume  of  carbonic  acid.  As  a  matter  of 
fact  it  may  vary  between  wide  limits,  and  it  is  with  water  gas  that 
the  test  for  this  substance  is  of  the  greatest  value.  In  the  Massa- 
chusetts report  above  referred  to  there  are  some  109  analyses  of 
water  gases,  and  of  these  34  have  between  2  and  3  per  cent  of 
carbonic  acid;  22  between  3  and  4  per  cent;  9  between  4  and  5 
per  cent;  6  between  5  and  6  per  cent,  and  7  between 6  and  9  per 
cent,  while  31  are  under  2  per  cent. 

Sulphuretted  Hydrogen.  The  fact  that  sulphur  is  found  in  illu- 
minating gas  is  due  to  its  presence  in  coal,  oil  and  carbide;  the 
amount  and  form  in  which  it  occurs  are  due  in  part  to  the  condi- 
tions prevailing  in  retort  or  generator  and  in  part  to  the  manner 
in  which  it  is  combined  in  the  coal.  A  good  gas  coal  will  have 
from  0.5  to  2.0  per  cent  of  sulphur;  it  may  even  be  used  with  as 
much  as  2.5  per  cent,  but  this  amount  should  never  be  exceeded, 
and  it  is  far  better  to  employ  a  coal  with  less  than  1.5  per  cent  of 
sulphur.  This  sulphur  may  be  present  in  the  coal  in  three  forms : 
(i)  as  sulphates,  (2)  as  sulphides,  (3)  in  combination  with 
organic  matter.  The  sulphate,  which  is  generally  present  as  a 
lime  salt,  is  not  volatile,  and  remains  with  the  coke  in  the  retort. 
The  sulphides  and  organic  compounds,  however,  when  heated  in 
the  reducing  atmosphere  of  the  retort  or  generator,  give  off  the 
greater  part  of  their  sulphur  in  the  form  of  sulphuretted  hydrogen, 
and  most  of  the  remainder  as  carbon  bisulphide. 

Butterfield  found  by  experiment  that  the  crude  gas  taken  from 
the  hydraulic  main  contained  on  an  average  1.2  per  cent  of  its 
volume  of  sulphuretted  hydrogen,  when  coal  containing  i.i  per 
cent  of  sulphur  was  being  carbonized.  This  ratio  is,  of  course, 
not  a  fixed  one,  and  it  has  been  found  that  the  higher  the  temper- 
atures of  distillation,  the  greater  the  amount  of  sulphur,  and 


CARBONIC    ACID  AND    SULPHURETTED   HYDROGEN         97 

especially  in  forms  other  than  sulphuretted  hydrogen,  which 
passes  into  the  gaseous  product.  After  leaving  the  retort  various 
reactions  may  take  place  between  the  components  of  the  gas. 
Hornby  states  that  the  ammonia  unites  with  a  part  of  the  sulphur- 
etted hydrogen,  carbonic  acid,  sulphurous  acid  and  cyanogen  to 
form  the  sulphydrate,  carbonate,  sulphite  and  cyanide  of  ammo- 
nium, while  other  reactions  produce  ammonium  sulphocyanate, 
ammonium  thiosulphate,  etc. 

Carburetted  water  gas  before  purification  contains  from  100  to 
150  grains  of  sulphuretted  hydrogen  per  100  cubic  feet  (0.15  to 
0.25  per  cent  by  volume)  and  small  amounts  of  sulphur  in  other 
forms.  Butterfield  states  that  he  has  never  seen  the  sulphur 
(exclusive  of  sulphuretted  hydrogen)  in  purified  water  gas  exceed 
10  grains  per  100  cubic  feet,  but  the  writer  has  analyzed  52  samples 
for  sulphur,  taken  from  water  gases  supplied  in  New  York  State 
during  1908,  where  the  total  sulphur  was  in  excess  of  10  grains; 
ten  of  these  had  over  15  grains  and  2  over  20  grains  per  100  cubic 
feet  of  gas,  and  no  sulphuretted  hydrogen  was  present. 

In  acetylene,  if  properly  made,  there  should  be  little  or  no 
sulphuretted  hydrogen.  If  the  gas  comes  from  a  hot  generator, 
however,  and  if  there  is  aluminum  sulphide  or  calcium  sulphide 
in  the  carbide,  sulphuretted  hydrogen  will  be  found  in  the  acetylene 
in  amounts  varying  from  o.oi  up  to  1.34  per  cent.  The  gas  is 
also  liable  to  contain  small  quantities  of  organic  sulphur  compounds 
which  Caro  contends,  and  probably  with  justice,  are  mustard 
oils  and  mercaptans. 

Now  the  presence  of  sulphuretted  hydrogen  in  illuminating 
gas  is  objectionable  for  several  reasons.  In  the  first  place,  it  is 
of  itself  poisonous,  and  from  its  odor  extremely  offensive.  More- 
over, it  acts  powerfully  on  most  of  the  metals,  as  may  be  seen  by 
exposing  for  a  moment  a  moistened  silver  coin  to  a  current  of  gas 
containing  sulphuretted  hydrogen,  when  a  black  metallic  film  of 
silver  sulphide  will  be  formed.  Furthermore,  its  products  of  com- 
bustion contain  sulphurous  and  sulphuric  acids  which  act  upon 
metals  and  leather  and  have  an  injurious  effect  upon  the  respira- 
tory tract.  There  seems  to  be  no  difference  of  opinion  as  to  the 


98  GAS   AND    GAS   METERS 

necessity  of  removing  sulphuretted  hydrogen  from  the  gas.  Hornby 
has  well  put  the  case  when  he  says:  "In  the  case  of  sulphuretted 
hydrogen,  however,  there  can  be  no  choice;  every  trace  of  this 
impurity  must  be  removed  or  the  gas  is  unfit  for  consumption." 
The  tests  for  this  obnoxious  constituent  become  then  of  prime 
importance;  but  since  no  trace  of  sulphuretted  hydrogen  is  to  be 
allowed  in  the  finished  product,  a  qualitative  test  of  the  latter  is 
usually  all  that  is  necessary.  It  is  often  desirable,  however,  to 
determine  the  efficiency  of  the  purifiers,  or  to  ascertain  the  amount 
of  sulphuretted  hydrogen  in  the  crude  gas,  and  therefore  one  or 
two  quantitative  methods  for  its  determination  will  be  given. 

The  mere  detection  of  the  presence  of  hydrogen  sulphide  is 
extremely  simple.  With  a  little  practice,  the  sense  of  smell  alone 
will  tell  the  observer  all  that  he  needs  to  know.  The  familiar 
odor  of  rotten  eggs  will  overcome  that  of  the  gas  itself,  even  when 
the  sulphuretted  hydrogen  is  present  in  minute  quantities  only. 
There  is  one  precaution  to  be  noted  in  this  connection.  In  the 
case  of  a  carburetted  water  gas,  the  oil  used  for  enrichment  some- 
times imparts  to  the  gas  an  odor  which  might  be  mistaken  for  that, 
of  sulphuretted  hydrogen.  The  test,  moreover,  is  not  sufficiently 
delicate  to  meet  all  requirements,  and  while,  if  the  odor  of  sul- 
phuretted hydrogen  is  really  detected,  there  can  be  no  doubt  as 
to  the  presence  of  that  impurity,  it  does  not  follow  that  if  the 
odor  is  not  detected  the  sulphuretted  hydrogen  is  entirely 
absent. 

A  qualitative  test,  which  is  simple  and  infallible,  consists  in 
moistening  a  strip  of  white  paper  with  a  solution  of  acetate  of 
lead  (sugar  of  lead)  and  exposing  it  to  a  current  of  the  gas  to  be 
tested.  If  sulphuretted  hydrogen  be  present,  the  paper  will 
become  covered  with  a  metallic,  brownish-black  layer  of  lead 
sulphide.  The  reaction  is, 

Pb(C2H302)2+  H2S  =  PbS  +  2C2H302. 

The  length  of  time  necessary  to  produce  this  discoloration  will 
also  give  some  idea  as  to  the  amount  of  the  sulphuretted  hydrogen 
present.  There  is  but  one  point  to  be  guarded  against;  it  some- 


CARBONIC    ACID   AND  SULPHURETTED   HYDROGEN         99 

times  happens  that  particles  of  oil  or  dust  from  the  burner  are 
blown  onto  the  paper  and  color  it  a  dirty  brown.  This  color 
has  no  metallic  luster  and  is  not  spread  evenly  over  the  paper, 
and  consequently  will  afford  no  trouble  to  a  practiced  observer. 
In  many  companies  in  the  United  States  it  is  the  custom  to  make 
a  continuous  test,  and  this  is  done  by  suspending  strips  of  paper, 
which  have  been  soaked  in  lead  acetate  solution  and  dried,  in  a  bell 
jar  through  which  the  gas  continually  flows.  The  dried  paper, 
however,  does  not  respond  as  quickly  to  the  action  of  the  sul- 
phuretted hydrogen  as  does  the  moist  paper,  and  since  the  latter 
takes  but  a  moment  to  prepare,  it  would  seem  to  be  preferable  to 
make  a  number  of  tests,  of,  say,  i  minute  each,  with  the  moist 
paper  in  preference  to  a  continuous  one  with  the  dry  paper.  To 
prepare  the  necessary  solution,  all  that  is  required  is  to  dissolve 
the  requisite  amount  of  lead  acetate  in  water.  The  proper  strength 
for  this  solution  seems  to  be  a  matter  of  opinion.  The  Metro- 
politan Gas  Referees  of  London  direct  that  6.5  grams  of  crystal- 
lized lead  acetate  be  dissolved  in  100  c.c.  of  water.  In  July,  1908,  an 
article  appeared  in  one  of  the  gas  journals  stating  that  the  proper 
strength  was  120  grams  to  the  liter.  Dr.  A.  A.  Noyes,  in  his 
" Qualitative  Analysis,"  suggests  that  as  a  reagent  lead  acetate 
should  be  prepared  by  dissolving  100  grams  Pb(C2H3O2)2 . 3  H2O 
in  i  liter  of  water.  It  is  doubtless  true  that  any  of  these  solu- 
tions will  give  perfect  satisfaction  if  made  from  pure  chemicals 
and  kept  from  access  to  the  air,  as  lead  acetate  reacts  readily  with 
carbonic  acid  to  form  a  white  precipitate  of  lead  carbonate,  and 
the  writer  has  met  with  solutions  which  had  become  so  exhausted 
in  this  way  that  the  clear  liquid  would  not  react  with  sulphuretted 
hydrogen.  It  should  be  needless  to  remark  that  the  test  for  sul- 
phuretted hydrogen,  as  well  as  all  tests,  chemical,  photometrical 
or  calorimetric,  should  be  made  with  gas  fresh  from  the  main, 
holder  or  other  source  of  supply. 

In  testing  acetylene  for  sulphuretted  hydrogen,  use  of  the 
moist  paper  is  not  recommended;  it  is  better  to  bubble  the  gas 
through  a  solution  of  lead  acetate  and  then  ignite  it  at  a  burner. 
The  appearance  of  a  brownish-black  precipitate  or  color  in 


100  GAS   AND   GAS   METERS 

the  lead  acetate  will  indicate  the  presence  of  sulphuretted 
hydrogen. 

For  the  quantitative  estimation  of  sulphuretted  hydrogen  in 
gas,  Sutton  recommends  the  method  and  apparatus  devised  by 
Mohr. 1  This  is  based  on  the  fact  that  when  sulphuretted  hydro- 
gen is  brought  into  contact  with  an  excess  of  arsenious  acid  in 
hydrochloric  acid  solution,  arsenious  sulphide  is  formed,  thus: 

As203  +  3  H2S  =  As2S3  +  3  H2O. 

The  arsenious  sulphide  settles  out  as  a  yellow  precipitate,  and  the 
excess  of  arsenious  acid  is  determined  by  titration  with  N/io 
iodine  solution  and  starch.  The  process  is  carried  out  as  follows: 
The  gas  is  led  into  two  successive  small  wash-bottles  containing 
a  dilute  solution  of  caustic  soda  or  potash;  from  the  last  of  these 
it  is  led  into  a  large  WoulfFs  bottle  filled  with  water.  The  bottle 
has  two  necks  and  a  tap  at  the  bottom;  one  of  the  necks  contains 
the  cork  through  which  the  tube  carrying  the  glass  is  led;  the 
other  a  cork  through  which  a  good  sized  funnel  with  a  tube  reach- 
ing to  the  bottom  of  the  bottle  is  passed.  When  the  gas  begins  to 
bubble  through  the  flask,  the  tap  is  opened  so  as  to  allow  the  water 
to  drop  rapidly;  if  the  pressure  of  gas  is  strong,  the  funnel  tube 
acts  as  a  safety  valve  and  allows  the  water  to  rise  up  into  the  cup 
of  the  funnel.  When  a  sufficient  quantity  of  gas  has  passed  into 
the  bottle,  say  6  or  8  pints,  the  water  which  has  issued  from  the 
tap  into  some  convenient  vessel  is  measured  in  cubic  inches  or 
liters  and  gives  the  quantity  of  gas  which  has  displaced  it.  In 
order  to  insure  accurate  measurement  all  parts  of  the  apparatus 
must  be  tight. 

The  flasks  are  then  separated,  and  in  the  second,  5  c.c.  of 
arsenious  solution  are  placed,  and  acidified  slightly  with  hydro- 
chloric acid.  If  any  traces  of  a  precipitate  occur,  it  is  set  aside 
for  titration  with  the  contents  of  the  first  flask,  to  which  10  c.c.  or 
so  of  arsenious  solution  are  added,  acidified  as  before,  both  mixed 
together,  diluted  to  a  given  measure,  filtered,  and  a  measured 
quantity  titrated  with  N/io  iodine  solution,  using  starch  as  an 

1  Sutton's  Volumetric  Analysis. 


CARBONIC    ACID   AND   SULPHURETTED   HYDROGEN       IOI 

indicator.  This  method  does  not  answer  for  very  crude  gas 
containing  large  quantities  of  sulphuretted  hydrogen,  unless  the 
absorbing  surface  is  largely  increased. 

The  arsenious  solution  is  a  N/io  solution  of  sodium  arsenite, 
and  is  made  by  dissolving  4.95  grams  of  the  purest  sublimed 
arsenious  oxide  reduced  to  powder  in  about  250  c.c.  of  distilled 
water  in  a  flask  with  about  20  grams  of  pure  sodium  carbonate. 
Warm  and  shake  for  some  time  until  solution  is  complete,  then 
dilute,  cool  and  make  up  to  one  liter.  The  N/io  solution  of  iodine 
is  prepared  in  the  following  manner:  Weigh  out  exactly  12.7  grams 
of  the  purest  iodine  and  about  18  grams  of  C.P.  potassium 
iodide  (free  from  iodate),  and  dissolve  the  two  together  in  about 
250  c.c.  of  water  and  dilute  to  i  liter.  This  solution  must  not  be 
heated,  as  iodine  is  volatile,  and  some  maybe  lost  as  a  vapor.  Keep 
in  a  glass-stoppered  bottle  in  a  cool  and  dark  place;  if  possible  keep 
the  bottle  completely  filled. 

The  starch  indicator  must  be  prepared  with  care,  as  upon  it 
depends  the  delicacy  of  the  end  point.  If  Kahlbaum's  soluble 
starch  can  be  obtained,  it  is  only  necessary  to  dissolve  0.5  gram  in 
25  c.c.  of  boiling  water,  allow  it  to  cool  and  bottle  it.  If  this  is  not 
obtainable,  take  one  part  of  clean  potato  starch,  mix  it  with  just 
enough  cold  water  to  form  a  smooth  emulsion,  and  then  gradually 
pour  this  into  200  times  its  weight  of  boiling  water,  stirring  con- 
stantly. Continue  to  boil  the  mixture  for  three  or  four  minutes, 
then  let  it  stand  till  the  suspended  matter  has  thoroughly  settled 
out,  and  decant  the  clear  solution  into  a  bottle.  This  solution 
should  be  made  fresh  at  least  every  three  or  four  days,  as  it  deteri- 
orates rapidly  on  standing. 

The  value  of  the  iodine  solution  is  found  by  titration,  as  follows : l 
Weigh  out,  into  two  No.  4  beakers,  two  portions  of  0.175  to  0-200 
gram  each  of  pure  arsenious  acid.  Dissolve  in  10  c.c.  of  caustic 
soda  solution  with  stirring.  Dilute  the  solutions  to  150  c.c.  and  add 
hydrochloric  acid  until  the  solution  contains  a  few  drops  in  excess, 
and  finally  add  a  concentrated  solution  of  5  grams  of  sodium  bi- 
carbonate. Cover  the  beakers  to  avoid  loss.  Add  the  starch  solu- 

1  Talbot's  Introductory  Course  of  Quantitative  Chemical  Analysis. 


IO2  GAS   AND    GAS   METERS 

tion  (5  c.c.  if  made  from  potato  starch,  i  to  2  c.c.  if  from  soluble 
starch),  and  titrate  with  the  iodine  to  the  appearance  of  the  blue  of 
the  iodo-starch,  taking  care  not  to  pass  the  end  point.  Arsenious 
acid  dissolves  more  readily  in  caustic  alkali  than  in  alkali  carbo- 
nates, but  the  presence  of  the  former  during  titration  is  not  admissi- 
ble, because  it  interferes  with  the  color  of  the  blue  iodide  of  starch. 
The  addition  of  hydrochloric  acid  destroys  this  caustic,  and  the 
solution  is  then  made  alkaline  with  a  bicarbonate.  Normal  carbo- 
nates cannot  be  used  for  the  same  reason  given  for  the  caustic 
alkali. 

Assume  that  0.200  gram  of  As2O3  required  41.2  c.c.  of  the  iodine 
solution.     The  reaction  is 

As2O3  +  2  I2  +  2  H2O  =  As2O5  +  4  HI. 
Therefore  198  :  508  :  :  0.2  :  x. 

oc  =  0.513  gram  of  iodine  in  41.2  c.c.  Then  i  c.c.  of  the  iodine 
solution  contains  0.01245  gram  of  iodine,  and  the  solution  is  0.098 
normal.  Knowing  the  strength  of  this,  it  is  easy  to  determine  the 
value  of  the  arsenious  solution  used  in  the  analysis.  From  a  glass- 
stoppered  burette1  run  25  c.c.  of  the  iodine  solution  into  a  flask, 
and  then  from  a  second  burette  add  the  arsenious  solution  until  the 
iodine  color  is  nearly  removed.  Then  add  the  starch  indicator  and 
continue  the  addition  of  the  arsenious  solution  drop  by  drop  until 
the  blue  color  just  disappears.  If  the  titrated  solution  is  allowed  to 
stand  for  a  short  time  exposed  to  the  air,  the  blue  color  will  return, 
due  to  the  oxidation  of  the  hydriodic  acid  by  the  oxygen  of  the  air. 
If  25  c.c.  of  the  iodine  solution  require  23.8  c.c.  of  the  arsenious 
solution,  i  c.c.  of  the  latter  equals  1.0504  c.c.  of  iodine.  It  also 
equals  (25  X  0.01245)  ~*~  23-8>  or  0.01308  gram  of  iodine. 

Then  As2O3  :  2  I2  :  :  x  :  0.01308 

198        508 

x  =  0.005098  gram  As2O3  to  i  c.c. 
Now 

As2O3  :  3  H2S  :  :  0.005098  :  x.          x  =  0.002626. 

1  Iodine  solutions  act  upon  rubber,  hence  only  burettes  with  glass  stopcocks 
should  be  used. 


CARBONIC  ACID  AND  SULPHURETTED  HYDROGEN   103 

So  i  c.c.  of  the  arsenious  solution  is  equivalent  to  0.002626  gram  of 
hydrogen  sulphide.  If  now  in  an  actual  determination  15  c.c.  of 
arsenious  solution  were  used,  0.5  cubic  foot  of  gas  corrected  was 
passed  and  10.2  c.c.  of  iodine  required  to  oxidize  the  excess  of 
arsenious  oxide,  then  the  calculation  will  proceed  thus:  i  c.c. 
iodine  equals  23.8  -r-  25  =  0.952  c.c.  of  the  arsenious  solution. 
15  —  (10.2  X  0.952)  =  5.29  =  number  of  cubic  centimeters  of 
arsenious  solution  used  up  by  the  sulphuretted  hydrogen  in  the 
gas.  But  i  c.c.  of  arsenious  solution  =  0.002626  gram  of  hydrogen 
sulphide,  therefore, 

5.29  X  0.002626  =  0.01389  gram  of  hydrogen  sulphide  in  0.5  cubic 

foot  of  gas. 
0.01389  X  15.43  X  200  =  42.86  grains  of  sulphuretted  hydrogen 

per  100  cubic  feet  of  gas. 

This  method  is  stated  by  Sutton,  one  of  the  greatest  authorities 
on  volumetric  analysis,  to  be  far  superior  to  the  direct  titration  of 
hydrogen  sulphide  by  iodine,  as  is  done  in  the  Tutweiler  or  U.  G.  I. 
test.  This  latter  method,  however,  is  simpler,  more  rapid  and  fairly 
accurate,  and  is  therefore  well  adapted  to  gasworks  use.  With 
this  process  a  measured  sample  of  gas  is  taken,  and  into  this  is  run 
a  standard  solution  of  iodine.  At  first  the  iodine  will  be  decolorized 
by  the  sulphuretted  hydrogen,  but  when  the  latter  is  exhausted, 
the  iodine  color  will  begin  to  appear.  The  burette  is  graduated 
to  read  direct  in  grains  of  sulphuretted  hydrogen  per  100  cubic  feet 
of  gas.  This  is  practically  the  same  as  the  method  of  Dupasquier,, 
who  draws  a  measured  quantity  of  gas  through  a  solution  of  iodine 
in  potassium  iodide,  to  which  some  starch  paste  has  been  added. 

The  operation  is  stopped  at  the  moment  when  the  solution 
becomes  colorless;  from  the  volume  of  gas  used  to  decolorize  a 
known  weight  of  iodine,  the  quantity  of  sulphuretted  hydrogen 
present  in  the  gas  may  be  easily  calculated.  The  reaction  is 

H2S  +  I2  =  2  HI  +  S 

if  the  solutions  are  very  dilute  and  direct  sunlight  is  excluded. 

If  a  gravimetric  method  is  desired,  proceed  exactly  as  in  the 
volumetric  method,  using  the  arsenious  solution  until  the  latter 


104  GAS    AND   GAS   METERS 

has  been  added.  Then  filter  off  the  arsenious  sulphide,  wash  it 
well  with  hot  water,  dry  at  100°  C.  and  weigh.  39.02  per  cent  of 
the  weight  of  arsenious  sulphide  is  sulphur,  and  hydrogen  sulphide 
equals  34/32  times  the  weight  of  sulphur.  Now  assume  10  cubic 
feet  of  gas  corrected  were  taken  and  the  weight  of  arsenious 
sulphide  was  3.7284  grams. 

3.7284  X  0.3902  X  15.43  X  100/10  X  34/32  =  238.5    grains    hy- 
drogen sulphide  per  100  cubic  feet. 

Since  the  factors  0.3902,  15.43,  34/32  and  100  are  constant  and 
occur  in  every  calculation,  they  may  be  combined  into  one  factor, 
thus:  100  X  0.3902  X  15.43  X  34/32  =  639.7. 

Therefore,  to  find  the  grains  of  sulphuretted  hydrogen  per  100 
cubic  feet  of  gas,  multiply  the  weight  of  arsenious  sulphide  by 
639.7  and  divide  by  the  volume  of  gas  used. 

The  Harcourt  method  for  sulphuretted  hydrogen  is  conducted 
in  the  same  general  manner  as  his  test  for  carbonic  acid,  save  that 
the  solution  through  which  the  gas  is  drawn  is  made  of  lead  ace- 
tate, and  the  standard  cylinder  contains  a  similar  solution  having 
a  color  equal  to  that  produced  by  the  action  of  a  definite  amount 
of  sulphuretted  hydrogen  on  lead  acetate.  The  gas  is  passed 
through  the  first  cylinder  until  the  color  therein  matches  the 
standard  color,  and  from  the  volume  of  gas  required  to  accom- 
plish this  the  quantity  of  sulphuretted  hydrogen  in  the  gas  is  easily 
calculated.  This  is  rapid  and  much  more  accurate  than  the 
similar  test  for  carbonic  acid,  principally  because  colors  or  inten- 
sity of  colors  and  not  turbidities  are  compared. 

To  determine  sulphuretted  hydrogen  in  acetylene,  Harcourt' s 
color  tubes  may  be  employed,  or  the  gas  may  be  passed  through 
a  solution  of  lead  acetate  in  one  or  more  flasks  or  wash-bottles, 
the  precipitate  of  lead  sulphide  filtered  off,  washed  with  hot 
water,  dissolved  in  dilute  nitric  acid,  and  the  solution  evaporated 
nearly  to  dryness.  Then  5  c.c.  of  concentrated  sulphuric  acid 
are  added  and  the  evaporation  continued  until  the  white  fumes  of 
sulphuric  acid  are  freely  given  off.  After  cooling,  dilute  carefully 
with  cold  water  and  add  double  the  volume  of  common  alcohol. 
Let  stand  until  all  of  the  lead  sulphate  has  settled  out;  filter,  and 


CARBONIC   ACID   AND   SULPHURETTED   HYDROGEN       1 05 

wash  the  precipitate  with  common  alcohol.  This  precipitate  may 
then  be  dried,  ignited  and  weighed;  or  it  may  be  dissolved  in 
ammonium  acetate,  made  up  to  100  c.c.  in  a  long  narrow  tube, 
sulphuretted  hydrogen  added  and  the  color  compared  with  that 
of  known  amounts  of  lead  in  similar  tubes  which  have  been  also 
treated  with  sulphuretted  hydrogen. 

Many  other  methods  have  been  devised,  such  as  Wanklyn's, 
Leicester  Greville's,  Folkard's,  L.  T.  Wright's,  and  Marshall's, 
but  for  the  details  of  these  the  reader  should  consult  Abady's 
"Gas  Analysts'  Manual." 

An  excess  of  sulphuretted  hydrogen  in  the  purified  gas  is  due  to 
one  of  five  causes:  (i)  Insufficient  purifying  capacity.  Newbig- 
ging  says  that  with  four  boxes,  three  of  which  are  in  continual 
use,  the  maximum  output  per  day  expressed  in  thousands,  multi- 
plied by  0.6  will  give  the  superficial  area  of  purifying  surface 
necessary.  If  only  two  boxes  are  used  at  a  time,  the  first  must 
always  be  changed  as  soon  as  foul  gas  appears  at  the  outlet. 
(2)  Exhausted  oxide.  This  is  easily  discovered,  if  after  revivi- 
fying, the  oxide  fails  to  remove  the  sulphuretted  hydrogen.  The 
remedy  is  apparent.  (3)  Poor  quality  of  oxide.  (4)  Too  rapid 
passage  of  the  gas  through  the  purifiers.  (5)  Channels  in  the 
oxide.  In  the  case  of  lime  purification,  if  the  lime  box  is  not 
followed  by  one  of  clean  oxide,  sulphuretted  hydrogen,  which  has 
been  regenerated  in  the  lime  box  by  the  action  of  carbonic  acid 
on  calcium  sulphydrate  (the  product  of  the  reaction  between  sul- 
phuretted hydrogen  and  slaked  lime),  may  pass  on  to  the  holder. 


CHAPTER  II. 
TOTAL  SULPHUR. 

As  has  already  been  stated,  the  sulphur  in  gas  exists  principally 
as  sulphuretted  hydrogen,  but  also  to  some  extent  as  carbon 
bisulphide  and  other  organic  compounds.  These  latter  are 
present  in  coal  gas,  as  it  leaves  the  condensers  to  the  extent  of 
about  0.024  to  0.042  per  cent  by  volume,  or  34  to  59  grains  per 
100  cubic  feet,  about  four-fifths  of  this  being  carbon  bisulphide. 
According  to  Hornby,  the  scrubbers  remove  about  2  grains  of 
carbon  bisulphide  per  100  cubic  feet  of  gas,  and  another  writer 
states  that  after  leaving  the  washers  the  gas  will  contain  on  an 
average  30  to  40  grains  of  sulphur  compounds,  exclusive  of  sul- 
phuretted hydrogen,  per  100  cubic  feet.  This  amount  is  too 
great  to  be  allowed  to  remain  in  the  finished  product,  and  in  many 
places  a  law  is  in  force  limiting  the  amount  of  total  sulphur  which 
may  be  permitted. 

The  reason  for  such  legislation  will  be  clear  after  a  moment's 
consideration  of  the  facts.  The  product  of  combustion  of  the 
sulphur  in  the  gas  is  sulphurous  acid.  This  of  itself  would  be 
disagreeable  and  dangerous  to  have  in  the  air  were  it  present  in 
sufficient  quantity,  but  even  this  is  only  an  intermediate  product 
in  many  cases.  In  the  presence  of  oxygen  and  moisture  sul- 
phurous acid  oxidizes  to  sulphuric  acid,  and  there  can  be  no  ques- 
tion as  to  the  danger  to  health  from  this  substance;  the  only  dis- 
cussion is  as  to  whether  there  can  be  enough  of  it  formed  in  a  room 
with  the  ordinary  means  of  ventilation,  to  render  its  presence  a 
menace.  One  or  two  opinions  of  eminent  authorities  are  quoted 
here  to  throw  light  on  the  subject. 

Major  C.  W.  Hinman  away  back  in  1878  said:  "I  am  of  the 
opinion  that  when  gas  containing  the  ordinary  amount  of  sulphur 

106 


TOTAL   SULPHUR  IO/ 

(less  than  20  grains)  is  burned,  and  the  ventilation  is  moderately 
effective,  the  damage  done  is  inconsiderable;  but  when  the  amount 
of  sulphur  much  exceeds  the  common  limit,  or  the  ventilation  is 
ineffective,  that  the  effect  on  persons  of  delicate  organization  is 
unpleasant  and  certain  objects  may  be  injured."  * 

Mr.  H.  Leicester  Greville  says,  referring  to  the  fact  that  the 
standard  for  sulphur  in  London  has  been  abolished:  "The  only 
rational  excuse  for  the  abrogation  of  the  proportion  of  sulphur 
compounds  must  have  been  the  introduction  of  the  incandescent 
burner.  Consumers  who  use  a  flat  flame  or  Argand  burner  would 
suffer  the  penalty  of  polluting  the  atmosphere  of  their  living  rooms 
with  the  amount  of  increased  sulphur  in  the  gas.  Those,  on  the 
other  hand,  who  use  the  incandescent  would  not  have  any  increased 
vitiation  or  pollution  owing  to  the  decreased  consumption.  Thus : 
with  a  flat-flame  burner  consuming  8  feet  per  hour  and  sulphur 
at  20  grains  per  100  cubic  feet,  the  illuminating  power  is  14  candle- 
power  and  the  sulphur  per  hour  1.6  grains.  With  an  incandescent 
burner  at  2  cubic  feet  per  hour  and  sulphur  at  (say)  50  grains  per 
100  cubic  feet,  the  illuminating  power  is  50  candlepower  and  the 
sulphur  per  hour,  one  grain."2 

The  Public  Control  Committee  of  the  London  County  Council, 
in  a  report  to  that  body  says :  "  The  Council  will  probably  remember 
that  we  were  not  in  favor  of  legislation  for  removing  the  restrictions 
with  regard  to  the  presence  of  sulphur  compounds  in  gas;  but  the 
companies  maintained  that  there  was  no  method  by  which  these 
compounds  could  be  removed  without  creating  a  nuisance  in  the 
process  of  purification." 2  They  go  on  to  say  that  before  the 
Act  of  1905  the  Referees  prescribed  the  maximum  for  sulphur  as 
17  and  22  grains  for  summer  and  winter  respectively.  For  1907, 
the  average  sulphur  in  gas  of  the  three  companies  in  London  was 
above  the  35  grains  which  the  companies  said  would  be  the  probable 
average  after  the  passage  of  the  Act  of  1905,  and  in  one  company 
it  was  very  considerably  above  it.  They  conclude  as  follows: 
"We  regard  the  question  as  one  which  very  seriously  affects  the 

1  Massachusetts  State  Gas  Inspector's  Report,  1878. 

2  Journal  of  Gas  Lighting,  June  n,  1907. 


108  GAS   AND   GAS   METERS 

interests  of  gas  consumers  generally,  and  we  therefore  propose  to 
ask  the  gas  companies  for  an  explanation  of  the  large  proportion 
of  sulphur  compounds  present  in  the  gas  supplied  by  them  and  for 
an  assurance  that  the  proportion  shall  be  reduced  in  the  near 
future."  l 

The  Lancet,  the  leading  British  medical  journal,  on  February  8, 
1908,  presented  evidence  of  the  presence  of  sulphuric  acid  in  the 
products  of  combustion  of  coal  gas:  "Over  the  ordinary  gas  light 
the  ceiling  paper  shows  always  more  or  less  discoloration  and  after 
a  time  becomes  charred,  crumbles  and  drops  off;  this  is  commonly 
attributed  to  the  deposition  of  soot,  when  often  it  is  really  the  effect 
of  sulphuric  acid  formed  in  the  combustion  of  the  gas  and 
deposited  on  the  ceiling."  The  Lancet  states  that  an  examination 
of  such  paper  shows  it  to  be  sour  to  the  taste  and  distinctly  acid  in 
reaction,  and  analysis  showed  as  much  as  16  grains  of  sulphuric 
acid  per  square  foot  of  paper. 

The  article  continues:  "It  seems  probable  that  the  presence  of 
sulphuric  acid  from  this  source,  in  the  course  of  time,  may  be  a 
source  of  injury  to  the  respiratory  tract,  manifesting  itself  par- 
ticularly in  catarrhal  inflammations  and  non-resistance  to  infec- 
tion."2 

To  state  the  other  side  of  the  case,  the  British  Act  of  1905, 
above  referred  to,  abolished  the  limit  for  sulphur  compounds 
other  than  sulphuretted  hydrogen,  and  as  the  English  have 
always  been  leaders  in  careful  and  painstaking  investigations  of 
gas  matters,  this  fact  is  of  great  weight. 

Again,  in  the  hearing  before  the  New  York  State  Commission 
of  Gas  and  Electricity  on  the  matter  of  fixing  standards  of  illumi- 
nating power  and  purity  of  the  gas  supplied  throughout  New 
York  State,  the  opinion  of  most  of  the  managers  of  gas  companies 
present  seemed  to  be  that  a  standard  for  total  sulphur  was  unneces- 
sary. The  observations  of  the  writer  in  New  York  State  would 
tend  to  make  him  of  this  opinion  also,  provided  that  the  gas  com- 
panies would  not  take  advantage  of  such  removal  of  restrictions 

1  Journal  of  Gas  Lighting,  May  26,  1908. 

2  Journal  American  Medical  Association,  March  28,  1908. 


TOTAL   SULPHUR  IOQ 

to  allow  the  total  sulphur  to  mount  up  as  it  has  done  in  London 
since  1906. 

During  the  year  1908  (to  December  ist)  some  677  tests  were 
made  of  the  gas  supplied  by  the  various  coal  and  water  gas  com- 
panies doing  business  in  the  state  of  New  York  outside  of  New 
York  City.  Of  this  number  only  28  showed  over  20  grains  of 
sulphur  per  100  cubic  feet,  and  but  5  of  them  were  over  25  grains, 
the  highest  amount  being  29  grains. 

On  the  other  hand,  in  Massachusetts  the  writer  has  seen  sulphurs 
of  over  40  grains  per  100  cubic  feet,  and  there  seems  to  be  little 
question  but  that  such  an  amount  may  be  a  menace  to  health  and 
property. 

Aside  from  all  these  considerations,  however,  two  facts  affect 
powerfully  the  question  of  a  limit  for  sulphur.  First,  in  very 
many,  if  not  most  of  the  cases  in  this  country  where  legislation 
has  been  enacted  to  regulate  the  gas  industry,  the  amount  of 
sulphur  which  may  be  present  in  gas  is  limited  to  a  definite  amount. 
Second,  the  policy  of  practically  all  of  the  gas  companies  to-day 
is  to  give  the  most  satisfactory  service  possible,  and  since  the 
people,  rightly  or  wrongly,  regard  sulphur  as  deleterious,  it  must  be 
kept  within  bounds. 

Although  lime  purification  is  becoming  scarce  in  this  country,  it 
may  be  well  to  say  just  a  word  as  to  the  manner  in  which  the 
sulphur  is  removed  by  this  process.  Carbon  bisulphide  is  not 
acted  on  by  either  calcium  hydrate  or  by  the  calcium  carbonate 
which  is  formed  by  the  reaction  of  the  carbonic  acid  in  the  gas 
with  the  lime.  It  does  react,  however,  with  the  calcium  sul- 
phydrate  (CaSH)  which  has  already  been  mentioned  as  the  product 
of  the  action  of  sulphuretted  hydrogen  on  slaked  lime,  and  cal- 
cium sulphocarbonate  is  formed.  Hence  the  lime  must  be  foul 
for  the  removal  of  carbon  bisulphide;  but  it  must  not  be  for- 
gotten that  if  carbonic  acid  reaches  this  foul  lime,  sulphuretted 
hydrogen  will  be  liberated  and  therefore  a  clean  box  of  oxide 
must  follow  the  last  lime  box. 

Oxide  of  iron  is  an  excellent  material  for  the  removal  of  sul- 
phuretted hydrogen,  but  its  powers  of  retention  for  carbon  bi- 


IIO  GAS    AND    GAS   METERS 

sulphide  are  small.  Newbigging  says:  "As  oxide  of  iron  pure 
and  simple,  it  has  no  affinity  for  carbon  bisulphide  and  other 
sulphocarbon  compounds,  but  from  the  observations  made  at  the 
several  Metropolitan  Gas  Works  Mr.  R.  H.  Patterson  (one  of  the 
Referees)  deduced  the  interesting  fact  that  the  sulphur  which  is 
present  in  a  state  of  minute  division  in  the  oxide  of  iron  after  the 
latter  has  been  in  use  for  some  time  and  frequently  revivified, 
possesses  the  power  of  arresting  a  portion  of  the  carbon  bisulphide." 
Dr.  H.  B.  Harrop,  in  his  "  Gas  Works  Chemistry,"  is  inclined  to 
disagree  with  this  opinion.  He  concludes  as  the  result  of  some 
very  thorough  experiments,  that  "the  sulphur  compounds  other 
than  sulphuretted  hydrogen  dropped  in  the  boxes  may  be  absorbed 
by  some  unidentified  organic  substances  deposited  there  from  the 
gas." 

Because  of  these  facts,  and  especially  because  the  amount  of 
sulphur  which  may  be  present  in  gas  is  in  many  localities  restricted 
by  law,  it  becomes  of  importance  to  learn  what  methods  have  been 
devised  for  the  estimation  of  carbon  bisulphide  and  total  sulphur. 
With  one  exception  these  methods  all  follow  the  same  general 
idea  of  burning  the  gas,  collecting  the  products  of  combustion, 
oxidizing  the  sulphurous  acid  to  sulphuric  acid,  and  determining 
the  latter  by  some  volumetric  or  gravimetric  method. 

The  single  exception  is  Harcourt's  color  test,  the  apparatus 
for  which  is  shown  in  Fig.  16.  a  is  a  burner  supporting  the  chim- 
ney, 6,  inside  of  which  is  suspended  the  bulb,  c.  This  bulb  is 
filled  with  platinized  pumice  and  is  held  in  place  by  the  clamp,  d, 
on  an  iron  ring  stand,  e,  in  such  a  manner  that  it  is  about  i  inch 
above  the  burner  and  in  the  center  of  the  chimney.  The  tube,  /, 
connects  with  the  gas  supply  and  passes  through  the  stopper  of  the 
bulb  down  into  the  pumice.  On  the  side  of  the  neck  is  an  out- 
let, g,  which  is  connected  with  a  capillary  tube  leading  through  the 
rubber  stopper  and  nearly  to  the  bottom  of  the  glass  cylinder,  h. 
One  end  of  a  short  tube,  i,  bent  at  right  angles  passes  through  the 
second  hole  in  the  rubber  stopper  and  projects  a  half-inch  into  the 
cylinder;  the  other  end  is  connected  with  the  aspirator,  j,  which 
is  entirely  filled  with  water  before  commencing  a  test,  k  is  a 


TOTAL   SULPHUR 


III 


graduated  cylinder,  the  divisions  on  which  may  express  cubic 
centimeters  or  fractions  of  a  cubic  foot.  The  cylinder,  m,  contains 
the  standard  solution,  and  n  is  a  sheet  of  white  cardboard. 

The  principle  on  which  the  apparatus  works  is  that  in  passing 
over  the  heated  platinized  pumice  the  carbon  bisulphide  in  the 
gas  becomes  converted  into  sulphuretted  hydrogen  which  is 
absorbed  in  a  solution  of  lead  acetate  contained  in  the  cylinder, 


Fig.  1 6.     Apparatus  for  Harcourt's  Color  Test. 

h,  and  the  color  of  such  solution  becomes  thereby  darker  and 
darker.  When  its  intensity  matches  that  of  a  solution  in  m 
containing  a  known  amount  of  sulphuretted  hydrogen,  the  flow 
of  gas  is  cut  off,  and  the  amount  used  is  determined  by  the  quan- 
tity of  water  which  has  passed  into  the  graduated  cylinder,  k. 

The  detailed  procedure  to  be  followed  with  this  apparatus  is 
as  follows:1  "To  use  the  apparatus  turn  on  first  the  upper  stop- 
cock, sending  gas  through  the  bulb  at  the  rate  of  about  one-half 
cubic  foot  per  hour,  as  may  be  judged  by  lighting  the  gas  for  a 
moment  at  the  end  of  the  horizontal  arm,  when  a  flame  about 
an  inch  in  length  should  be  produced.  Light  the  burner  and 

1  Abady's  Gas  Analyst  Manual. 


112  GAS  AND   GAS   METERS 

turn  down  the  flame  till  it  forms  a  blue  non-luminous  ring,  then 
place  the  small  clay  pieces  upon  the  top  of  the  chimney  round 
the  neck  of  the  bulb.  A  testing  may  be  made  five  minutes  after  the 
burner  is  lit,  except  when  the  apparatus  is  first  used,  when  the 
gas  should  be  allowed  to  flow  through  the  bulb  for  a  quarter  of 
an  hour  or  a  little  longer,  and  any  number  of  testings  may  be 
made,  one  after  another,  as  long  as  the  heat  is  continued. 

"The  mode  of  testing  is  as  follows:  Place  the  piece  of  opal 
glass  in  the  back  of  the  comparison  box.  (The  figure  shows  a 
sheet  of  cardboard,  but  a  small  box  which  takes  the  Standard 
Color  and  the  Test  Tube  and  which  has  an  opal  back,  is  now 
used.)  Put  the  Standard  Color  Tube  in  one  of  the  holes  in  the 
box.  Now  dilute  some  of  the  lead  syrup  solution  with  about  20 
times  its  volume  of  distilled  water,  and  fill  the  test  glass  up  to  the 
mark  with  the  solution  thus  prepared.  Insert  the  caoutchouc 
plug  with  capillary  tube  (which  should  descend  very  nearly  to 
the  bottom  of  the  glass,  but  must  not  press  upon  the  bottom,  or  it 
will  probably  be  broken)  and  elbow  tube,  and  connect,  as  shown 
in  the  figure,  with  the  bulb  and  aspirator,  placing  the  two  glasses 
side  by  side  in  the  comparison  box. 

"There  are  two  color  standards,  one  for  daylight  and  the  other 
for  gaslight,  which  are  sent  out  in  sealed  glasses.  When  using 
the  gaslight  standard,  the  gaslight  employed  should  be  a  flat 
flame  or  Argand,  emitting  yellow  rays;  the  incandescent  (white 
mantle)  will  not  do.  The  glass  containing  the  standard  solution 
should  always  be  shaken  before  commencing  a  test. 

"The  aspirator  must  be  quite  full  of  water  at  starting,  and  the 
measuring  cylinder  empty.  Turn  the  tap  of  the  aspirator  grad- 
ually; a  stream  of  bubbles  will  rise  through  the  solution  of  lead. 
Turn  off  the  tap  for  a  minute  and  observe  the  liquid  at  the  bottom 
of  the  capillary  tube.  If  it  gradually  rises,  the  India  rubber  con- 
nections are  not  air  tight  and  must  be  made  so  before  proceed- 
ing. Avoid  pressing  the  plugs  into  the  glass  or  the  aspirator 
while  they  are  connected,  which  would  drive  up  the  lead  solution 
into  the  inlet  tube. 

"  When  the  connections  are  air  tight,  let  the  water  run  into  the 


TOTAL   SULPHUR  113 

measuring  cylinder  in  a  slender  stream  until  the  lead  solution  has 
become  as  dark  as  the  standard.  As  the  ascending  bubbles  inter- 
fere somewhat  with  the  observation  of  the  tint,  it  is  best  to  turn 
off  the  tap  when  the  color  seems  almost  deep  enough;  compare 
the  two;  turn  on  the  tap,  if  necessary,  for  a  few  moments,  then 
compare  again  and  so  on  until  the  color  of  the  two  liquids  is  the 
same.  The  volume  of  water  which  the  measuring  cylinder  now 
contains  is  equal  to  the  volume  of  gas  which  has  passed  through 
the  lead  solution." 

The  calculations  involved  in  computing  the  result  will  be  made 
clearer  by  a  concrete  illustration.  Assume  that  the  standard 
solution  contains  0.0121  gram  or  0.187  grain  of  lead  sulphide, 
that  the  measuring  cylinder  is  divided  into  cubic  centimeters, 
and  that  2492  c.c.  of  water  have  passed  from  the  aspirator  to  this 
cylinder : 

PbS  :  S  :  :   O. 187  :  x 

239    32 

oc  =  0.025  grain.  So.  the  standard  solution  contains  0.025 
grain  of  sulphur,  and  since  the  test  solution  has  been  made  to 
match  the  standard  in  color,  enough  sulphuretted  hydrogen  must 
have  passed  into  it  so  that  it  too  contains  0.025  grain  of  sulphur. 
Then  2492  c.c.  which  are  equal  to  0.088  cubic  foot,  contain 
0.025  grain  of  sulphur  as  carbon  bisulphide. 

0.025  X  I0°  "*•  -°88  =  28.4  grains  of  sulphur  as  carbon  bisul- 
phide per  100  cubic  feet  of  gas. 

This  does  not  give  the  total  sulphur  in  the  gas,  for  the  reason 
that  carbon  bisulphide  is  not  the  only  form  in  which  sulphur 
exists  in  the  gas,  and  the  other  varieties  are  not  converted  to 
sulphuretted  hydrogen  by  the  action  of  heat.  Abady  states  that 
these  other  compounds  contain  sulphur  which  ordinarily  amounts 
to  7  or  8  grains  per  100  cubic  feet,  and  this  quantity  must  there- 
fore be  added  to  that  found  by  the  analysis  in  order  to  arrive  at 
the  total  sulphur  in  the  gas.  Thus  it  is  clear  that  the  method  is 
only  an  approximation  at  best. 

Moreover,  as  will  be  readily  seen,  the  test  cannot  be  conducted 
upon  gas  containing  sulphuretted  hydrogen;  in  such  cases  the 


114  GAS   AND   GAS   METERS 

latter  must  be  removed  by  an  oxide  purifier  before  the  gas  reaches 
the  apparatus.  There  are  one  or  two  other  precautions  which 
should  be  noted.  For  each  separate  experiment  the  test  cylinder 
must  be  emptied,  rinsed  and  recharged.  The  solutions  must  not 
be  allowed  to  become  heated,  as  thereby  the  color  is  intensified. 
It  is  a  little  difficult  to  see  how  this  can  be  avoided,  since  hot  gas 
is  passed  into  one  of  the  tubes,  and  this  fact  would  seem  to  detract 
from  the  value  of  the  results.  The  test  solution  may  be  used 
again  and  again,  provided  it  is  exposed,  after  each  determination, 
to  the  action  of  light  for  a  few  hours,  whereby  it  again  becomes 
colorless.  Air  must,  however,  be  excluded  during  the  process,  as 
otherwise  carbonic  acid  acts  on  the  lead  acetate,  forming  lead 
carbonate,  and  the  strength  of  the  solution  is  thereby  diminished. 

The  platinized  pumice  will  serve  for  100  tests;  after  that  its 
action  is  weakened  by  the  deposition  of  carbon  on  its  surface. 
It  may  be  revivified,  however,  by  heating  it  rather  hotter  than  is 
customary  during  a  test,  and  drawing  air  over  its  surface.  The 
carbon  is  oxidized  to  carbonic  acid  and  passes  off  into  the  aspir- 
ator; the  process  is  complete  when  the  air  which  has  been  drawn 
through  is  passed  through  a  solution  of  barium  hydrate  and 
creates  no  cloudiness,  thus  proving  that  carbonic  acid  is  no  longer 
being  formed. 

This  process  of  determining  total  sulphur  has  not  been  adopted 
to  any  extent  in  this  country,  and  does  not,  in  the  writer's  opinion, 
compare  favorably  with  either  the  Referees'  method,  or  another 
which  will  be  described  shortly  and  which  was  devised  by  Major 
C.  W.  Hinman  and  perfected  by  Mr.  C.  D.  Jenkins.  Before 
coming  to  these  most  important  methods,  however,  a  short  de- 
scription must  be  given  of  two  other  processes  which  are  recom- 
mended by  high  authorities. 

The  method  of  Wildenstein  consists  in  burning  the  gas  in  a 
Referees'  apparatus  in  the  manner  prescribed  in  the  Referees' 
test,  collecting  the  products  of  combustion  and  making  them  up 
to  a  definite  volume.  A  portion  of  this  representing  a  known 
volume  of  gas  is  then  placed  in  a  beaker  or  porcelain  dish  and 
acidified  slightly  with  hydrochloric  acid.  The  solution  is  heated 


TOTAL   SULPHUR  115 

to  boiling,  and  a  known  volume  of  a  standard  solution  of  barium 
chloride  is  added,  in  amount  more  than  sufficient  to  unite  with  all 
of  the  sulphuric  acid  present.  Ammonia  is  then  cautiously  added 
until  the  solution  is  just  neutral  and  the  excess  of  barium  chloride 
titrated  with  a  standard  solution  of  potassium  chromate.  This 
method  is  both  convenient  and  accurate,  but  the  directions  must 
be  followed  in  detail,  or  the  reliability  of  the  results  is  lost.  The 
sulphur  from  the  gas  is  present  in  the  solution  as  sulphuric  acid; 
the  barium  chloride  unites  with  this  to  form  barium  sulphate,  thus : 

BaCl2  +  H2SO4  =  BaSO4  +  2  HC1. 

This  barium  sulphate  is  a  heavy  white  precipitate  very  insoluble 
in  water  and  dilute  hydrochloric  acid;  the  boiling  facilitates  both 
the  formation  of  this  precipitate  and  its  settling  out.  As  has 
been  seen  from  the  reaction,  hydrochloric  acid  is  formed,  and  this 
must  be  neutralized  because  barium  chromate  is  soluble  in  dilute 
hydrochloric  acid,  producing  a  solution  with  a  yellowish  to  red- 
dish color  which  would  obscure  the  end-point  of  the  titration. 
As  the  potassium  chromate  is  added,  it  unites  with  the  excess  of 
barium  chloride,  thus: 

K2CrO4  +  BaCl2  =  BaCrO4  +  2  KC1. 

The  barium  chromate  is  a  heavy  yellow  precipitate  insoluble  in 
neutral  or  alkaline  solutions  and  settling  out  readily  from  the 
boiling  liquid.  As  long  as  the  barium  chloride  remains .  in  the 
solution,  the  supernatant  liquid  will  be  colorless;  but  the  moment 
enough  potassium  chromate  has  been  added  to  unite  with  all  of 
the  barium  chloride,  the  solution  will  be  colored  yellow,  and  this 
is  the  desired  end-point. 

The  barium  chloride  and  potassium  chromate  are  made  by 
dissolving  52  grams  of  the  former  and  48.5  grams  of  the  latter  in 
water  and  making  the  volume  of  each  solution  up  to  i  liter,  thus 
making  both  N/2.  One  cubic  centimeter  of  either  is  then  equal 
to  i  c.c.  of  the  other  and  to  0.02  gram  of  SO3;  therefore  in 
making  the  calculation  it  is  only  necessary  to  deduct  the  number 
of  cubic  centimeters  of  potassium  chromate  used  from  the  num- 


Il6  GAS   AND   GAS   METERS 

her  of  cubic  centimeters  of  barium  chloride  added  and  multiply 
the  difference  by  0.02  to  get  the  grams  of  SO3  in  the  amount  of 
liquid  tested;  and  as  .4  of  SO3  is  sulphur,  the  result  is  readily 
calculated  to  grains  per  100  cubic  feet  of  gas. 

Example.  Ten  cubic  feet  of  gas  were  burned  and  the  products 
of  combustion  made  up  to  200  c.c.  Fifty  c.c.  of  these  were  taken 
for  analysis,  10  c.c.  of  the  barium  chloride  added  and  5.8  c.c.  of 
the  potassium  chromate  required  to  combine  with  the  excess  of 
barium  chloride. 

10.0  —  5.8  =  4.2  c.c. 

4.2  X  0.02  =  0.084  gram  SO3  in  the  50  c.c. 

but  S  =  0.4  of  SO3  and  i  gram  =  15.43  grains, 

therefore  0.084  X  0.4  X  15.43  =  0.5184  grain  sulphur  in  50  c.c. 
The  total  volume  of  the  sample  was  200  c.c.  and  represented 
10  feet  of  gas,  so  0.5184  X  200/50  X  100/10  =  20.7  grains  of 
sulphur  per  100  cubic  feet.  Or,  if  one-fourth  of  the  total  solution 
is  always  taken  for  analysis,  we  can  combine  the  various  factors 
and  deduce  the  following  formula  for  finding  the  grains  of  sulphur 
per  100  cubic  feet  of  gas: 

(B  -  K)  X  49.36 
G 

where  B  equals  the  number  of  cubic  centimeters  of  barium 
chloride  added,  K  equals  the  number  of  cubic  centimeters  of 
potassium  chromate,  and  G  the  cubic  feet  of  gas  burned. 

If  the  method  is  to  be  employed  only  for  water  gas,  it  will  be 
better  to  use  the  entire  sample  for  analysis,  or  else  to  make  the 
standard  solutions  much  weaker,  say  20.8  grams  of  barium  chloride 
and  19.4  grams  of  potassium  chromate  to  the  liter  respectively, 
in  either  of  which  cases  the  above  formula  would  have  to  be 
modified. 

Mr.  W.  C.  Young  takes  an  aliquot  part  of  the  liquor  given  by 
the  Referees'  apparatus,  adds  sufficient  acetic  acid  to  decompose 
any  ammonium  carbonate  which  may  be  present,  and  then  a 
measured  excess  of  a  standard  solution  of  barium  chloride.  The 


OF   THE 

UNIVERSITY 

OF 


TOTAL   SULPHUR  1 1/ 

solution  is  next  evaporated  to  dryness  in  a  platinum  dish  and 
heated  to  low  redness;  the  contents  are  cooled  and  washed  out 
into  a  beaker,  an  excess  of  potassium  chromate  added  and  a  stand- 
ard solution  of  silver  nitrate  run  in  from  a  burette  until  the  red 
color  of  the  silver  chromate  remains  permanent. 

The  idea  of  the  process  is  to  precipitate  the  sulphuric  acid  with 
an  excess  of  barium  chloride,  and  then  by  expelling  all  hydro- 
chloric acid  and  ammonium  chloride  from  the  solution,  to  deter- 
mine the  amount  of  barium  chloride  which  has  not  been  needed  to 
combine  with  the  sulphuric  acid  by  titration  with  silver  nitrate. 
Since  hydrochloric  acid  and  ammonium  chloride  are  both  volatile, 
their  expulsion  is  for  the  most  part  easily  accomplished;  but  to 
remove  traces  which  are  held  within  the  solid  residue,  it  is  necessary 
to  heat  to  low  redness.  Silver  nitrate  reacts  with  barium  chloride 
and  potassium  chromate  as  follows: 

2  AgNO3  +  BaCl2     =  2  AgCl  +  Ba(NO3)2, 
2  AgNO3  +  K2CrO4  =  Ag2CrO4  +  2  KNO3. 

The  first  of  these  reactions  is  the  one  which  will  take  place  so 
long  as  there  is  any  barium  chloride  left  in  the  solution,  but  the 
moment  it  is  exhausted  the  second  reaction  sets  in.  The  silver 
chloride  is  a  heavy  white  precipitate,  while  the  silver  chromate  is 
deep  red;  consequently  the  end-point  is  very  sharp.  The  amount 
of  silver  nitrate  used  in  the  titration  is  equivalent  to  the  excess  of 
barium  chloride  added,  or,  in  other  words,  to  the  amount  of  barium 
chloride  left  over  after  all  of  the  sulphuric  acid  has  been  converted 
to  barium  sulphate.  Now  the  solutions  may  be  made  up  so  that 
i  c.c.  of  the  barium  chloride  equals  5  c.c.  of  the  silver  nitrate,  and 
the  latter  should  be  N/20  and  contain  8.499  grams  to  the  liter. 
The  potassium  chromate  is  a  10  per  cent  solution;  that  is,  100 
grams  to  the  liter. 

Now,  assuming  that  the  products  of  combustion  from  10  cubic 
feet  of  gas  were  made  up  to  100  c.c.  and  10  c.c.  taken  for  analysis; 
15  c.c.  of  barium  chloride  were  added,  and  it  required  37.5  c.c.  of 
silver  nitrate  to  react  with  the  excess.  37.5  c.c.  of  silver  nitrate 
equals  7.5  c.c.  of  barium  chloride.  15  —  7.5  =  7-5  c-c-  °f  barium 


n8 


GAS  AND   GAS   METERS 


chloride  used  in  uniting  with  the  sulphuric  acid.  7.5  X  0.026 
(the  weight  of  barium  chloride  in  i  c.c.)  =  0.195  gram  barium 
chloride. 

BaCl2  :  S  :  :  0.195  :x 

208        32 

x  =  0.03  gram  of  sulphur  in  the  10  c.c.  analyzed.  0.03  X  10  X 
10  X  15.43  =  46.29  grains  of  sulphur  per  100  cubic  feet  of  gas. 
The  principal  advantage  of  this  test  is  its  rapidity,  one  complete 
determination  (after  securing  the  products  of  condensation) 
requiring  only  about  20  minutes.  Its  accuracy  is  sufficient  for 


From  Governor 
and  S    H2  test 

Fig.   17.     Referees' Sulphur  and  Ammonia  Apparatus. 

practical  purposes,  but  it  is  believed  that  one  of  the  methods 
already  given,  or  that  of  Mr.  Jenkins  which  follows,  will  be  found 
to  be  more  satisfactory  in  the  long  run. 

The  Referees'  method  is  the  one  officially  used  in  London,  and 
has  been  adopted  by  many  gas  companies  in  the  United  States. 
The  apparatus  necessary  is  seen  in  Fig.  17.  a  is  a  small  Bunsen 
burner  with  a  steatite  tip  which  projects  upward  through  a  cylin- 
drical metallic  stand,  b.  This  stand  has  a  gutter-like  depression 
running  round  the  upper  and  inner  edge,  in  which  rests  the  large 
end  of  the  glass  trumpet  tube,  c.  The  stand  is  perforated,  in  both 
sides  and  top,  with  14  circular  holes  of  about  5  mm.  diameter; 


TOTAL   SULPHUR  119 

these  serve  to  admit  the  air  required  for  combustion  of  the  gas. 
The  burner  pillar  is  surrounded,  when  the  apparatus  is  in  use, 
by  about  2  ounces  of  commercial  sesquicarbonate  of  ammonia, 
in  small  lumps;  these  rest  on  the  cylinder  and  lie  between  the 
burner  and  the  trumpet  tube,  d  is  a  glass  cylinder  or  bead  glass 
with  a  tubulure  at  the  bottom  and  a  constriction  between  this  and 
the  upper  part  of  the  cylinder.  This  bead  glass  is  filled  with 
marbles  or  balls  of  glass,  each  about  15  mm.  in  diameter,  which 
serve  to  expose  a  large  surface  to  the  current  of  combustion 
products  and  thus  promote  condensation. 

At  the  bottom  of  the  bead  glass  is  a  small  outlet  tube  of  glass, 
through  which  the  condensate  runs  into  the  beaker,  e.  A  long 
glass  tube,/,  is  connected  to  the  top  of  the  cylinder  and  serves  a 
threefold  purpose,  first  as  an  outlet  for  the  uncondensed  gases, 
second  as  a  regulator  for  the  draft,  third  as  a  condenser  for  any 
condensible  substances  which  may  have  passed  through  the 
cylinder.  The  wooden  stand,  g,  serves  to  support  the  beaker  and 
bead  glass.  The  manner  of  using  this  apparatus  is  prescribed 
with  great  exactness  by  the  Metropolitan  Gas  Referees:  "It  is  to 
be  set  up  in  a  room  or  closet  where  no  other  gas  is  burning.  The 
gas  shall  pass  through  a  meter  by  reference  to  which  the  rate  of 
flow  can  be  adjusted,  and  which  is  provided  with  a  self-acting 
movement  for  shutting  off  the  gas  when  10  cubic  feet  have  passed. 

"Pieces  of  sesquicarbonate  of  ammonia,  from  the  surface  of 
which  any  efflorescence  has  been  removed,  are  to  be  placed  round 
the  stem  of  the  burner.  The  index  of  the  meter  is  to  be  then 
turned  forward  to  the  point  at  which  the  catch  falls  and  will  again 
support  the  lever-tap  in  the  horizontal  position.  The  lever  is 
made  to  rest  against  the  catch  so  as  to  turn  on  the  gas.  The 
index  is  turned  back  to  a  little  short  of  zero  and  the  burner  lighted. 
When  the  index  is  close  to  zero  the  trumpet  tube  is  placed  in 
position  on  the  stand  and  its  narrow  end  connected  with  the 
tubulure  of  the  condenser.  At  the  same  time  the  long  chimney 
tube  is  attached  to  the  top  of  the  condenser. 

"As  soon  as  the  testing  has  been  started  a  first  reading  of  the 
aerorthometer  is  to  be  made  and  recorded,  and  a  second  reading  as 


I2O  GAS   AND   GAS   METERS 

near  as  may  be  to  the  time  at  which  the  gas  is  shut  off.  The  rate 
of  burning,  which  with  practice  can  be  judged  very  nearly  by  the 
height  of  the  flame,  is  to  be  adjusted,  by  timing  the  index  of  the 
meter,  to  about  half  a  cubic  foot  of  gas  per  hour. 

"  After  each  testing,  the  flask  or  beaker,  which  has  received  the 
liquid  products  of  the  combustion  of  the  10  cubic  feet  of  gas,  is  to 
be  emptied  into  a  measuring  cylinder  and  then  replaced  to  receive 
the  washings  of  the  condenser.  Next  the  trumpet  tube  is  to  be 
removed  and  well  washed  out  into  the  measuring  cylinder.  The 
condenser  is  then  to  be  flushed  twice  or  thrice  by  pouring  quickly 
into  the  mouth  of  it  40  or  50  c.c.  of  distilled  water.  These  washings 
are  brought  into  the  measuring  cylinder,  whose  contents  are  to 
be  well  mixed  and  divided  into  two  equal  parts. 

1  'One-half  of  the  liquid  so  obtained  is  to  be  set  aside,  in  case  it 
should  be  desirable  to  repeat  the  determination  of  the  amount  of 
sulphur  which  the  liquid  contains. 

"  The  other  half  of  the  liquid  is  to  be  brought  into  a  flask,  or 
beaker  covered  with  a  large  watch-glass,  treated  with  hydro- 
chloric acid  sufficient  in  quantity  to  leave  an  excess  of  acid  in  the 
solution,  and  then  raised  to  the  boiling  point.  An  excess  of  a 
solution  of  barium  chloride  is  now  to  be  added,  and  the  boiling 
continued  for  5  minutes.  The  vessel  and  its  contents  are  to 
be  allowed  to  stand  till  the  barium  sulphate  has  settled  at  the  bot- 
tom of  the  vessel,  after  which  the  clear  liquid  is  to  be  as  far  as 
possible  poured  off  through  a  paper  filter.  The  remaining  liquid 
and  barium  sulphate  are  then  to  be  brought  on  to  the  filter,  and 
the  latter  is  to  be  well  washed  with  hot  distilled  water.  (In  order 
to  ascertain  whether  every  trace  of  barium  chloride  and  ammonium 
chloride  has  been  removed,  a  small  quantity  of  the  washings  from 
the  filter  should  be  placed  in  a  test  tube,  and  a  drop  of  a  solution 
of  silver  nitrate  added;  should  the  liquid,  instead  of  remaining 
perfectly  clear,  become  cloudy,  the  washing  must  be  continued 
until  on  repeating  the  test  no  cloudiness  is  produced.) 

"  Dry  the  filter  with  its  contents,  and  transfer  it  into  a  weighed 
platinum  crucible.  Heat  the  crucible  over  a  lamp,  increasing  the 
temperature  gradually,  from  the  point  at  which  the  paper  begins 


TOTAL   SULPHUR  121 

to  char,  up  to  bright  redness.1  When  no  black  particles  remain, 
allow  the  crucible  to  cool ;  place  it  when  nearly  cold  in  a  desiccator 
over  strong  sulphuric  acid,  and  again  weigh  it.  The  difference 
between  the  first  and  second  weighings  of  the  crucible  will  give 
the  number  of  grains  of  barium  sulphate.  Multiply  this  number 
by  ii  and  divide  by  4;  the  result  is  the  number  of  grains  of  sulphur 
in  100  cubic  feet  of  the  gas. 

"This  number  is  to  be  corrected  for  the  variations  of  temperature 
and  atmospheric  pressure  in  the  manner  indicated  under  the  head 
of  Illuminating  Power,  with  this  difference,  that  the  mean  of  the 
first  and  second  aerorthometer  readings  shall  be  taken  as  the 
reading." 

The  aerorthometer  (Fig.  18)  is  an  instrument  for  correcting  the 
volume  of  a  gas  measured  over  water,  at  any  ordinary  temperature 
and  pressure,  to  that  which  the  gas  would  have  if  measured  over 
water  under  a  pressure  of  30  inches  of  mercury,  and  at  a  tempera- 
ture of  60°  F.  Thus  its  reading  corresponds  to  the  figure  derivable 
from  a  reading  of  the  barometer  and  the  thermometer  and  a  refer- 
ence to  a  table  giving  the  tension  of  aqueous  vapor  at  different 
temperatures.  The  instrument  consists  of  a  bulb  and  vertical 
stem  in  which  sufficient  water  is  present  to  insure  that  the  air  is 
saturated. 

The  measuring  tube,  which  terminates  in  a  closed  bulb,  and  a 
companion  tube  of  the  same  calibre,  which  is  open  to  the  air,  dip 
into  a  reservoir  of  mercury  in  the  base,  the  capacity  of  which  can  be 
adjusted  by  a  regulating  screw  pressing  on  a  leather  cover.  The 
relative  volume  of  the  bulb  and  tube  down  to  any  division  is  repre- 
sented by  the  number  belonging  to  that  division.  The  capillary 
tube  above  the  bulb  is  closed  by  a  very  small  amount  of  sealing 
wax. 

In  order  to  adjust  the  instrument,  the  sealing  wax  is  softened 
by  heat  and  a  small  hole  made  through  it.  When  the  bulb  has 
acquired  the  temperature  of  the  air,  the  regulating  screw  is  to  be 
turned  until  the  two  columns  of  mercury  stand  level  at  the  calcu- 

1  "  An  equally  good  and  more  expeditious  method  is  to  drop  the  filter  with  its 
contents,  drained  but  not  dried,  into  the  red-hot  crucible." 


122 


GAS   AND    GAS   METERS 


-I 
.1 


Fig.    18.     Aerorthometer. 


TOTAL   SULPHUR  123 

lated  aerorthometer  reading.  Then  the  sealing  wax  stopping  is 
again  melted  where  it  was  perforated,  by  being  touched  from  above 
with  a  heated  wire  while  the  base  of  the  tube  and  the  bulb  are  pro- 
tected from  heat  by  a  wrapping  of  cotton  wool. 

In  using  the  aerorthometer,  turn  the  screw  up  until  the  level  of 
the  mercury  in  the  open  tube  is  some  distance  below  that  of  the 
mercury  in  the  bulb  tube;  then  turn  the  screw  slowly  down  until  the 
mercury  stands  at  the  same  level  in  both  tubes.  The  division  at 
which  the  mercury  now  stands  is  the  aerorthometer  reading.  This 
instrument  is  not  in  much  use  in  this  country.  It  costs  about  $12.50 
in  England,  which  would  probably  mean  $15  or  $16  in  the  United 
States. 

Alexander  Wright  &  Co.,  who  manufacture  and  sell  all  of  the 
apparatus  recommended  by  the  Referees,  say  in  their  catalogue: 
".  .  .  We  consider  it  an  unreliable  instrument  for  general  use." 
The  correction  which  the  aerorthometer  affords  may  be  arrived  at 
equally  well  by  consulting  the  table  of  corrections  for  temperature 
and  pressure  and  tension  of  aqueous  vapor,  which  is  given  in  the 
appendix,  or  it  may  be  reached  by  the  percentage  method,  as  has 
been  explained  under  the  candlepower  calculations. 

The  theory  involved  in  the  Referees'  method  for  total  sulphur  is 
as  follows :  A  definite  volume  of  gas  is  burned,  and  the  sulphur 
is  converted  to  SO3.  This  passes  up  through  the  condenser  and 
draws  with  it  ammonia  vapor  from  the  ammonium  carbonate  around 
the  burner  tube.  In  the  presence  of  water  the  ammonia  and  sul- 
phuric anhydride  unite  to  form  ammonium  sulphate.  Thus, 

2  NH3  +  SO3  +  H2O  =  (NH4)2SO4. 

The  carbon  in  the  gas  burns  to  carbonic  acid,  which  unites  with 
the  water  and  ammonia  vapor  to  form  ammonium  carbonate.  The 
hydrogen  of  the  gas  burns  to  water  vapor,  which  furnishes  part  of 
the  water  necessary  for  the  above  reaction.  On  passing  over  the 
enormous  condensing  surface  offered  by  the  glass  marbles,  the  car- 
bonate and  sulphate  of  ammonium  and  the  aqueous  vapor  con- 
dense and  run  back  into  the  beaker. 

This  condensate  is  made  up  to  a  definite  volume  and  one-half 


124  GAS   AND    GAS   METERS 

taken  for  analysis.  To  this  half  hydrochloric  acid  is  added  for  two 
reasons :  first,  to  break  up  the  ammonium  carbonate  present,  which 
would  otherwise  react  with  the  barium  chloride  to  form  barium  car- 
bonate, a  heavy  white  precipitate,  which  would  then  be  weighed 
with  the  barium  sulphate  and  thus  give  too  high  results  for  the  sul- 
phur; second,  because  barium  sulphate  must  be  precipitated  in  a 
solution  slightly  acid  with  hydrochloric  acid. 

Heating  the  solution  to  boiling  drives  off  the  carbonic  acid,  which 
is  thus  eliminated  from  further  consideration.  It  also  renders  the 
formation  of  barium  sulphate  more  complete  and  rapid.  The  con- 
tinued boiling  after  addition  of  barium  chloride  brings  the  precipi- 
tate together  in  a  form  in  which  it  will  settle  rapidly.  The  solution 
is  then  allowed  to  stand  until  the  precipitate  has  settled;  this 
renders  filtration  more  rapid,  and  also  diminishes  the  possibility 
of  any  barium  sulphate  passing  through  the  filter,  as  sometimes 
happens. 

The  precipitate  always  contains  small  amounts  of  barium 
chloride  and  ammonium  chloride  mechanically  inclosed,  and 
these  are  removed  by  washing  with  hot  water.  If  cold  water 
were  used,  not  only  would  it  require  a  longer  time  to  dissolve 
out  the  impurities,  but  also  the  water  would  be  almost  certain  to 
carry  some  of  the  barium  sulphate  through  the  filter.  The  wash- 
ings are  tested  for  chlorine  with  silver  nitrate,  and  when  a  pre- 
cipitate or  cloudiness  no  longer  occurs  on  the  addition  of  the 
reagent,  it  is  clear  that,  if  the  washing  has  been  conscientiously 
performed,  the  precipitate  no  longer  contains  any  chlorides. 

The  platinum  crucible  must  be  ignited  when  empty  and  cooled 
in  a  desiccator  before  weighing;  this  is  to  drive  off  the  film  of 
moisture  and  dust  which  settles  on  the  surface  of  the  crucible. 
In  igniting  the  precipitate  care  must  be  taken  that  the  burning 
carbon  does  not  reduce  the  barium  sulphate  to  barium  sulphide; 
the  best  method  to  prevent  this  is  to  ignite  the  filter  and  pre- 
cipitate separately.  This  as  a  rule,  however,  cannot  be  done  in 
the  analysis  of  gas  for  sulphur,  because  the  barium  sulphate  pre- 
cipitate will  be  too  small,  and  will  not  separate  readily  from  the 
filter. 


TOTAL   SULPHUR  125 

The  next  best  method  is  to  place  the  uncovered  crucible  on 
the  ring  stand  at  an  angle  to  the  vertical,  and  apply  a  small  flame 
well  back  on  the  side  and  bottom  of  the  crucible,  so  that  there 
may  be  the  freest  possible  access  of  air.  The  weights  in  this 
country  will  usually  be  expressed  in  grams;  the  calculation  is 
then  explained  thus:  Assume  barium  sulphate  found  to  equal 
0.8275  gram  from  one-half  of  the  sample  obtained  by  burning 
10  cubic  feet  of  gas  corrected  for  temperature,  pressure  and  ten- 
sion of  aqueous  vapor. 

0.8275  X  2  X  10  =  16.55  grams  of  barium  sulphate  per  100 
cubic  feet  of  gas.  To  change  this  to  grains  multiply  by  15.43 
and  we  get  255.37  grains  of  barium  sulphate  from  100  cubic  feet 
of  gas.  Now  every  grain  of  barium  sulphate  contains  32/233 
grains  of  sulphur;  this  is  obtained  from  the  relation  of  the 
atomic  weight  of  sulphur,  32,  to  the  molecular  weight  of  barium 
sulphate,  233.  255.37  X  32/233  =  35.07  grains  of  sulphur  per 
100  cubic  feet  of  gas.  Or,  to  combine  all  of  these  factors  into  a 
rule:  When  10  cubic  feet  of  gas  (corrected)  are  burned,  and 
one-half  of  the  sample  is  taken  for  analysis,  multiply  the  weight 
of  barium  sulphate  in  grams  by  42.38,  and  the  result  will  be 
grains  of  sulphur  per  100  cubic  feet. 

This  method  is  accurate  provided  the  gravimetric  analysis  is 
carried  out  with  great  care  and  by  one  accustomed  to  chemical 
manipulation.  It  is,  however,  very  slow,  as  considerable  time  is 
consumed  in  waiting  for  the  barium  sulphate  to  settle,  in  filter- 
ing, drying,  igniting,  waiting  for  the  crucible  to  cool  and  in 
weighing.  Also  much  of  the  sesquicarbonate  of  ammonia  on 
the  market  contains  ammonium  bicarbonate,  and  the  excessive 
carbonic  acid  from  this  is  said  to  materially  interfere  with  the 
condensation  of  the  sulphurous  and  sulphuric  acids. 

Again,  a  considerable  amount  of  gas  is  required,  in  order  to 
secure  a  precipitate  of  barium  sulphate  sufficiently  large  to  handle, 
and  the  burning  of  10  cubic  feet  of  gas  at  a  rate  of  0.5  cubic  foot 
per  hour  is  a  long  and  tedious  process. 

Moreover,  where  a  large  number  of  tests  are  to  be  made,  a 
number  of  platinum  crucibles  are  required,  and  these  cost  from 


126  GAS   AND   GAS   METERS 

$20  apiece  upward.  Certain  of  the  volumetric  processes  have 
been  proven  to  be  just  as  accurate,  far  more  rapid,  and  requiring 
no  expensive  apparatus;  hence  it  would  seem  the  wisest  policy 
to  adopt  one  of  these.  Such  a  method  has  been  used  by  the 
writer  for  many  years,  and  has  given  perfect  satisfaction.  For 
the  sake  of  brevity,  it  will  be  alluded  to  as  the  Hinman- Jenkins 
method. 

The  apparatus  needed  for  this  method  is  described  in  the 
Journal  of  the  American  Chemical  Society  for  April,  1906,  and  is 
illustrated  in  Fig.  19.  a  is  a  bead  glass  12  inches  long  and  2.4 
inches  in  diameter.  This  is  filled  with  large  cut  glass  beads  about 
three-sixteenths  inch  in  diameter,  which  are  kept  from  drop- 
ping through  the  lower  opening  by  a  flower-shaped  piece  of  glass 
(see  Fig.  20),  or  by  a  watch-glass  with  a  number  of  V-shaped 
openings  cut  in  its  circumference.  This  bead  glass  offers  a  large 
condensing  surface  to  the  products  of  combustion,  and  at  the 
same  time  the  draft  is  not  interrupted,  b  is  a  glass  adapter  16.4 
inches  long,  2  inches  in  diameter  at  the  larger  end  and  three- 
fourths  inch  diameter  at  the  upper.  This  is  connected  to  the 
bead  glass  by  a  short  piece  of  heavy  rubber  tubing  wired  to  the 
constricted  part  of  the  bead  glass,  c  is  a  connecting  piece  join- 
ing the  upper  to  the  lower  adapter,  d,  which  is  16  inches  long, 
1.6  inches  in  diameter  at  the  large  end  and  one-half  inch  diameter 
at  the  small  end.  This  connecting  piece  is  composed  of  a  glass 
piece,  e,  in  shape  similar  to  the  adapters  but  only  5  inches  long, 
thirteen-sixteenths  inch  diameter  at  the  top,  and  three-eighths 
inch  diameter  at  the  bottom.  This  passes  through  a  rubber 
stopper  2  inches  in  diameter  at  the  smaller  end,  and  projects 
nearly  one-half  inch  above  the  stopper  into  the  upper  adapter. 

The  upper  end  of  the  glass  piece  is  roofed  over  by  a  watch- 
glass  if  inches  in  diameter  supported  on  platinum  wires  and  one- 
eighth  to  three-sixteenths  inch  above  the  end  of  the  glass  piece; 
this  serves  to  deflect  the  products  of  condensation  and  keep  them 
from  running  down  into  the  lower  adapter.  An  overflow  tube, 
/,  passes  just  through  the  stopper  and  leads  to  a  100  c.c.  Erlen- 
meyer  flask,  g,  in  which  the  condensate  collects.  The  overflow 


TOTAL   SULPHUR 


127 


tube  is  enough  above  the  level  of  the  stopper  so  that  a  little  water 

always  remains  on  the  latter  and  thus  keeps  it 

cool.     The  bottom  of  the  glass  piece  is  fitted 

into  a  cork  bound  by  a  brass  band,  and  the 

lower  adapter  fits  into   the  other  end  of  this 

cork. 

The  Bunsen  burner,  h,  carries  a  lava  tip  with 
an  opening  0.2  inch  in  diameter,  while  near  the 
base  for  the  pillar  are  two  other  holes  for  the 
admission  of  air.  Surrounding  the  pillar  is  a 
glass  tube  0.8  inch  in  diameter  and  ij  inches 
long  which  fits  into  the  center  of  a  section  of 
a  large  rubber  stopper.  This  stopper  itself 
fits  tightly  into  a  glass  cylinder  2  inches  in 
diameter  and  2  inches  long,  and  rests  upon 
and  within  a  cylindrical  iron  base,  i. 

Around  the  top  of  the  bead  glass  a  brass 
ring  one-half  inch  wide  is  sweated  on,  which 
serves  as  support  for  the  cord  by  which  the 
entire  apparatus  (save  the  burner)  is  suspended. 
The  complete  outfit  costs  $20.  It  may  be 
readily  set  up  or  taken  apart  in  three  minutes, 
and  the  individual  pieces  packed  in  a  small 
space  for  transportation. 

The  method  of  procedure  with  this  apparatus 
is  as  follows:  The  bead  glass  is  suspended 
by  its  cord  from  a  gas  fixture,  hook  or  nail ;  the 
rubber  stopper  is  inserted  in  the  upper  adapter, 
and  the  small  end  of  the  latter  is  forced  into 
the  rubber  connection  so  as  to  make  a  tight 
joint  with  the  bead  glass.  The  lower  adapter 
is  then  fastened  into  the  cork  connector,  the  Fig< 
Erlenmeyer  suspended  from  a  hook  in  the 
stopper,  and  over  the  mouth  of  the  overflow 
tube,  and  the  apparatus  is  ready  for  use.  Care 
must  be  taken  to  see  that  the  whole  column  is  vertical,  and  that 


19.  Hinman- 
Jenkins  Sulphur 
Apparatus. 


128  GAS   AND    GAS   METERS 

the  connections  are  tight.  The  bottom  of  the  lower  adapter 
should  be  at  such  a  height  above  the  floor  that  when  the  lamp 
is  inserted  the  adapter  will  project  about  one-fourth  to  one-half 
inch  within  the  outer  glass  ring  of  the  burner. 

The  gas  to  be  tested  is  connected  with  a  meter  and  then  with 
the  burner.  The  latter  is  lighted,  and  3  to  4  c.c.  of  a  10  per  cent 
solution  of  ammonia  are  placed  in  the  chamber  formed  by  the 
inner  and  outer  glass  rings.  As  the  hand  of  the  meter  passes 
zero,  the  burner  is  inserted  under  the  adapter  by  pulling  the 
latter  slightly  from  the  vertical,  pushing  in  the  lamp,  and  then 
returning  it  to  the  vertical  position. 

Record  the  reading  of  the  meter  at  the  start.  0.8  cubic  foot  of 
gas  is  to  be  burned  at  a  rate  not  exceeding  0.6  foot  per  hour,  and 
after  each  0.2  foot  has  passed,  2  c.c.  to  3  c.c.  of  ammonia  are 
added  to  the  burner  chamber,  without  disturbing  its  position. 
All  of  the  air  which  is  supplied  to  the  burner  must  pass  over  this 
ammonia,  consequently  the  SO2  and  SO3  formed  from  the  sulphur 
in  the  gas  meet  everywhere  throughout  the  apparatus  an  ammoni- 
acal  atmosphere,  and  so  condense  as  ammonium  sulphate  and 
ammonium  sulphite  and  run  back  with  the  water  formed  by  the 
combustion  into  the  Erlenmeyer  flask. 

To  avoid  labor  in  calculation,  it  is  well  at  the  start  to  note  the 
temperature  and  pressure,  and  ascertain  how  much  gas  must  be 
registered  on  the  meter  in  order  to  have  used  0.8  foot  at  normal 
temperature  and  pressure.  Thus,  if  the  temperature  is  72  degrees 
and  the  barometer  30.12  inches  and  the  meter  is  2.4  per  cent  slow, 
the  corrections  are:  temperature  (dry  meter)  2.4  per  cent  plus, 
barometer  0.4  per  cent  minus,  and  meter  2.4  per  cent  minus. 
Combining  these  we  get  0.4  per  cent  minus.  0.8  -r-  1.004  =  °-797- 
Consequently,  if  the  reading  on  the  meter  shows  0.797  fr)Ot>  °-8 
foot  corrected  will  have  been  used. 

Of  course  any  dry  meter  may  be  used;  a  wet  meter  is  not  rec- 
ommended because  of  the  solvent  action  of  the  water  and  because 
the  latter  will  give  up  to  the  gas,  and  take  from  it,  certain  sub- 
stances, such  as  ammonia,  sulphuretted  hydrogen,  etc.,  the  seem- 
ingly contradictory  action  depending  on  changes  of  temperature 


TOTAL   SULPHUR  1 29 

and  quality  of  the  gas.  A  small  3-diaphragm  meter,  known  as 
an  "O"  light,  is  in  use  by  the  writer  and  his  assistants,  and  has 
given  very  fair  satisfaction.  The  dial  is  horizontal,  thus  enabling 
one  to  read  it  without  stooping  over.  The  top  is  fastened  in  place 
by  screws  and  so  may  be  easily  removed  to  adjust  the  meter  or 
clean  the  valves.  This  meter  should  be  tested  as  often  as  prac- 
ticable, and  its  error  included  in  the  calculations,  as  was  done 
above.  Its  cost  is  $40,  and  it  may  be  procured  of  the  American 
Meter  Company. 

When  the  0.8  foot  of  gas  has  been  consumed,  shut  off  the  gas 
and  allow  the  apparatus  to  cool.  Disconnect  the  lower  adapter 
and  pour  distilled  water  through  one  end,  holding  the  other  end 
over  the  bead  glass.  When  the  entire  inner  surface  has  been 
touched  by  the  running  water,  the  adapter  is  laid  aside,  and 
water  poured  through  the  bead  glass,  in  small  quantities  at  a 
time,  until  about  150  c.c.  have  been  used.  As  the  Erlenmeyer 
flask  will  not  hold  this  amount,  it  may  be  emptied  at  any  time 
into  a  numbered  200  c.c.  sample  bottle,  and  replaced  in  position. 
This  can  easily  be  done  without  loss,  if  the  bottle  is  held  under 
the  overflow  tube  while  the  flask  is  being  emptied.  Allow  a  minute 
or  two  for  the  bead  glass  to  drain,  then  disconnect  the  upper 
adapter,  with  the  rubber  stopper  still  in  place,  from  the  bead 
glass,  and  wash  out  the  connecting  piece.  All  of  the  washings 
are  transferred  to  the  bottle,  and  the  sample  is  ready  for  analysis. 
The  latter  is  performed  in  a  manner  different  from  any  of  those 
methods  already  described.  The  reagents  employed  and  their 
preparation  will  now  be  given. 

(a)  Bromine  water.      This  is  made  by  covering  the  bottom 
of  a  250  c.c.  bottle  with  pure  bromine,  filling  the  bottle  with  dis- 
tilled water  and  shaking.     When  sufficient  of  the  bromine  has 
been  dissolved,  the  supernatant  liquid  will  be  of  a  deep-red  color. 
This  must  be  kept  in  a  glass-stoppered  bottle,  and  should  not  be 
exposed  to  direct  sunlight  or  to  heat. 

(b)  A  solution  of  barium  chromate  in  hydrochloric  acid,  con- 
taining 92  grams  of  pure  barium  chromate  dissolved  in  a  mixture 
of  120  c.c.  strong  hydrochloric  acid  (Sp.  Gr.  1.2)  and  880  c.c.  of 


130  GAS   AND   GAS   METERS 

water.  As  in  most  laboratories  250  c.c.  of  this  reagent  will  last 
for  months,  the  following  directions  cover  the  preparation  of 
this  amount.  It  is  difficult  to  secure  barium  chromate  of  the 
requisite  purity,  and  the  best  results  are  obtained  by  making  it 
on  the  spot. 

Take  22.2  grams  of  pure  BaCl2 .  2  H2O  and  dissolve,  in  a  750  c.c. 
beaker,  in  about  250  c.c.  of  distilled  water.  In  another  beaker 
dissolve  14  grams  of  pure  potassium  bichromate  in  250  c.c.  of 
water.  Heat  both  solutions  to  boiling  and  pour  one  into  the 
other,  stirring  all  the  while.1  Cover  the  beaker  with  a  watch- 
glass  and  let  stand  several  hours,  or,  better,  over  night,  in  a  warm 
place. 

Decant  the  supernatant  liquid  through  a  filter;  wash  the  pre- 
cipitate by  decantation  two  or  three  times  with  hot  water,  and 
finally  bring  it  on  the  filter  and  continue  the  washing  until  the 
wash  water  shows  no  trace  of  chlorine  or  chromium.  To  deter- 
mine this,  take  10  c.c.  of  the  wash  water  in  each  of  two  test-tubes; 
to  one  add  nitric  acid  and  silver  nitrate,  when  if  chlorine  be  present 
a  white  turbidity  or  opalescence  will  appear.  To  the  other  add 
acetic  acid  and  lead  acetate,  and  if  a  yellow  precipitate  is  formed, 
or  a  yellow  color  appears,  it  is  a  sign  that  the  chromium  has  not 
been  completely  washed  from  the  precipitate.  If  a  9  cm.  filter 
is  used,  it  will  be  difficult  to  perform  the  washing  satisfactorily, 
because  of  the  bulk  of  the  precipitate;  hence  it  is  better  to  divide 
the  latter  between  three  filters. 

When  chlorine  and  chromium  no  longer  appear  in  the  filtrate, 
the  barium  chromate  is  ready  for  use.  Dissolve  it  in  a  mixture 
of  30  c.c.  of  hydrochloric  acid  and  220  c.c.  of  water,  heated  to 
boiling,  and  if  the  solution  is  not  clear,  filter  it. 

In  the  finished  product  there  must  not  be  an  excess  of  either 
barium  or  chromate,  even  in  trifling  amount,  and  it  is  therefore 
always  advisable  to  test  the  solution  for  these  substances.  This 
may  be  done  by  taking  10  c.c.  of  the  barium  chromate  in  a  test 

1  As  the  reaction  sets  free  hydrochloric  acid,  in  which  barium  chromate  is 
soluble,  it  is  well  to  just  neutralize  the  acid  formed  with  ammonia,  thus  increasing 
the  yield  of  barium  chromate. 


TOTAL   SULPHUR  131 

tube,  adding  ammonia  until  just  alkaline,  and  filtering.  The 
barium  chromate  is  insoluble  in  alkaline  solution,  and  so  precipi- 
tates out;  while  if  the  solution  contains  any  barium  chloride  or 
potassium  bichromate,  they  will  pass  into  the  filtrate,  which  is 
to  be  divided  into  two  equal  parts. 

To  one-half  add  a  few  drops  of  hydrochloric  acid  and  then  dilute 
sulphuric  acid,  when,  if  barium  be  present,  a  white  precipitate 
will  be  formed.  To  the  other  half  add  acetic  acid  and  lead  ace- 
tate, and  a  yellow  precipitate  or  color  will  indicate  the  presence 
of  chromium.  In  case  the  test  for  barium  gives  positive  results, 
enough  potassium  bichromate  must  be  added  to  the  main  solu- 
tion to  exactly  react  with  this  barium,  and  another  test  made  to 
see  that  this  has  been  accomplished.  Conversely,  if  chromium 
is  found  to  be  present,  barium  chloride  must  be  added  until  the 
excess  is  entirely  neutralized. 

(c)  A  solution  of  ammonia  made  by  diluting  one  part  of  strong 
ammonia  with  8  to  10  parts  of  water. 

(d)  Stannous  chloride  solution,  containing  about  13  grams  of 
tin  to  the  liter.     It  is  well  to  make  up  a  stock  of,  say,  4  liters  of 
this  reagent,  as  it  is  somewhat  troublesome  to  prepare  and  may, 
with  proper  precautions,  be  kept  for  a  long  time.     13  grams  of  pure 
tin  are  placed  in  each  of  four  loo-c.c.  Erlenmeyer  flasks,  50  c.c.  of 
hydrochloric  acid  (1.2)  added  to  each,  and  a  piece  of  platinum  to 
aid  in  the  solution.     By  heating  and  allowing  to  stand,  as  much  of 
the  tin  as  possible  is  brought  into  solution;  this  will  require  a  long 
time  if  the  tin  is  pure,  but  need  not  take  up  the  entire  attention  of 
the  operator.     Filter  the  contents  of  all  four  flasks  through  one 
filter,  receiving  the  filtrate  in  a  750  c.c.  beaker.     Add  200  c.c.  of 
strong  hydrochloric  acid  to  this  filtrate,  pour  into  a  large  bottle  and 
make  up  to  4  liters. 

(e)  Starch  solution,  the  manufacture  of  which  has  already  been 
described  under  Mohr's  method  for  sulphuretted  hydrogen. 

(/)  Potassium  iodide  solution.  —  Dissolve  3  or  4  crystals  of  pure 
potassium  iodide  in  25  c.c.  of  water. 

(g)  Solution  of  potassium  ferricyanide.  —  i  gram  in  10  c.c.  is 
sufficient,  as  it  should  be  made  up  afresh  every  time  it  is  needed. 


132  GAS   AND   GAS   METERS 

(h)  Standard  solution  of  potassium  bichromate,  containing 
about  20  grams  to  the  liter.  It  is  necessary  to  know  the  exact 
strength  of  this  solution,  as  it  is  used  to  determine  the  value  of  the 
stannous  chloride  each  time  the  latter  is  used.  To  standardize, 
weigh  out  very  accurately  about  0.5  gram  of  purest  iron  wire,  dis- 
solve in  a  little  hydrochloric  acid,  dilute  to  about  50  to  75  c.c.,  and 
place  this  solution  in  a  Florence  flask  provided  with  a  Bunsen  valve. 
The  latter  is  made  up  of  a  rubber  stopper  through  which  projects  a 
piece  of  glass  tubing  about  3  inches  long.  To  the  upper  end  of  the 
tube  is  connected  a  piece  of  rubber  tubing  ii  inches  long,  closed  at 
the  top  by  a  glass  rod.  This  rubber  has  a  slit  one-fourth  inch  long, 
cut  through  one  wall  midway  between  the  rod  and  the  glass  tubing 
which  serves  as  outlet  for  the  steam,  but  which,  when  the  heat  is 
removed  from  the  flask  and  the  contents  begin  to  cool  and  condense, 
closes  automatically  and  prevents  the  entrance  of  air,  thus  produc- 
ing a  partial  vacuum  in  the  flask. 

Now  to  the  solution  of  iron  wire  in  the  glass,  add  i  gram  of  very 
pure  zinc  (free  from  iron),  insert  the  valve  and  heat  gently  until  all 
of  the  zinc  is  dissolved ;  by  this  time  the  air  will  have  been  expelled 
and  replaced  by  hydrogen  and  steam.  Remove  the  lamp  and  allow 
the  flask  and  contents  to  cool.  Open  the  slit  in  the  valve  and  take 
out  the  stopper.  Add  the  potassium  bichromate  to  be  tested  from 
a  burette  until  a  small  drop  of  the  liquid  from  the  flask,  placed  on  a 
white  porcelain  tile  in  contact  with  a  drop  of  the  potassium  ferri- 
cyanide,  no  longer  produces  a  blue  or  greenish-blue  color.  The 
end-point  is  somewhat  difficult  to  read,  and  a  little  time  spent  in 
practice  with  this  will  be  well  employed. 

The  process  is  based  on  the  fact  that  potassium  bichromate  will 
oxidize  a  solution  of  ferrous  chloride,  in  presence  of  hydrochloric 
acid,  to  ferric  chloride;  and  the  moment  when  sufficient  has  been 
added  is  shown  by  the  test  with  the  potassium  ferricyanide,  which 
gives  a  blue  precipitate  or  coloration  with  ferrous  salts  and  a  color- 
less solution  with  ferric  salts.  The  reactions  involved  are : 

Fe  +  2  HC1  =  FeCl2  +  H2 

6FeCl2  +  K2Cr2O7  +  14  HC1  =  6  FeCl3  +  2  KC1  +  2  CrCl3  +  7  H2O 
2  K3Fe(CN)6  +  3  FeCl2  =  Fe3(Fe(CN)e)2  +  6  KC1. 


TOTAL   SULPHUR  133 

The  iron  wire  sold  for  standardizing  purposes  generally  contains 
99.8  per  cent  of  iron,  and  allowance  is  made  for  this  and  for  the 
amount  of  iron  in  the  zinc  used.  This  latter  item  can  be  easily 
ascertained  by  buying  chemicals  whose  analysis  is  furnished  by  the 
manufacturer.  To  cite  a  specific  case:  0.5082  gram  of  iron  wire 
was  taken,  i  gram  of  zinc  containing  0.015  Per  cent  °f  iron  was  used 
for  reduction  of  the  iron,  and  21.60  c.c.  of  the  potassium  bichromate 
were  required.  (0.5082  X  0.998)  +  0.00015  =  °-5°73  grams  of 
iron,  which  reacted  with  the  potassium  bichromate. 

0.5073  H-  21.6  =  0.02349  gram  of  iron  per  cubic  centimeter  of 
bichromate. 

6  Fe  :  K2Cr2O7  ::  0.02349  :  x 
336  294 

x  =  0.02055  gram  of  potassium  bichromate  per  cubic  centimeter 
or  20.55  grams  per  liter. 

In  standardizing  the  stannous  chloride,  which  is  done  each 
time  before  using,  5  c.c.  of  the  potassium  bichromate  are  placed 
in  a  Florence  flask,  slightly  acidified  with  hydrochloric  acid,  and 
the  stannous  chloride  run  in  from  a  burette  until  nearly  the  proper 
amount  has  been  added.  This  quantity  may  be  estimated,  if 
necessary,  by  a  preliminary  titration.  Then  two  drops  of  the 
potassium  iodide  are  added  and  two  drops  of  starch  solution  and 
the  titration  continued,  adding  the  stannous  chloride  drop  by 
drop,  until  the  muddy,  greenish  appearance  of  the  liquid  sud- 
denly changes  to  a  clear  peacock-blue  green.  This  end-point  is 
extremely  sharp,  is  brought  about  by  less  than  one  drop  of  stan- 
nous chloride,  and  when  once  seen  can  never  be  mistaken.  It  is 
unnecessary  to  figure  the  value  of  the  stannous  chloride  at  this 
stage,  as  will  be  seen  when  the  final  calculation  is  considered. 

In  carrying  out  the  process,  the  sample  of  200  c.c.  is  emptied 
into  a  shallow  porcelain  dish,  which  is  then  marked  with  the  same 
number  as  that  borne  by  the  sample  bottle.  Enough  bromine  water 
is  added  to  color  the  solution  decidedly  reddish;  this  is  to  oxidize 
to  sulphuric  acid  any  sulphurous  acid  which  may  have  been 
formed.  The  dish  is  now  placed  over  a  small  Rose  burner  and 


134  GAS   AND    GAS    METERS 

the  contents  evaporated  to  about  25  c.c.  Care  must  be  taken 
that  the  flame  does  not  play  upon  the  dish  above  the  surface  of 
the  liquid,  or  ammonium  sulphate  will  be  lost  by  volatilization. 
Allow  the  liquid  to  cool,  add  2  c.c.  of  the  barium  chromate,  and 
wash  down  the  sides  of  the  dish  with  a  stream  from  a  wash-bottle. 

Heat  the  solution  to  boiling  and  then  add  enough  of  the 
ammonia  solution  so  that  a  faint  smell  of  ammonia  remains; 
this  will  require  only  a  few  c.c.  An  insufficient  amount  will 
result  in  too  high  a  figure  for  the  sulphur,  while  too  much  will 
interfere  with  the  future  work.  It  is  better,  however,  to  add  too 
much  rather  than  too  little,  since  the  excess  may  be  easily  removed 
by  boiling.  Boil  the  solution  for  a  minute  or  two  after  adding 
the  ammonia,  let  the  precipitate  settle,  filter,  wash  twice  by  decan- 
tation  and  once  on  the  filter. 

Place  the  filtrate  in  a  numbered  Florence  flask  of  125  c.c. 
capacity,  insert  a  rubber  stopper  bearing  a  Bunsen  valve,  and 
boil  the  solution  until  all  air  in  the  flask  has  been  expelled  and 
steam  has  issued  freely  for  some  minutes  from  the  orifice  in 
the  valve.  Place  the  flask  in  cold  water  and  leave  there  until  the 
contents  have  attained  the  room  temperature.  Then  remove  the 
stopper,  add  hydrochloric  acid  to  distinctly  acid  reaction,  and  run 
in  the  stannous  chloride  until  the  yellow  color  of  the  solution  has 
nearly  disappeared.  Now  add  two  drops  of  potassium  iodide 
and  a  few  c.c.  of  starch  (if  made  from  soluble  starch)  and  con- 
tinue the  titration  until  the  solution  becomes  colorless.  Read 
and  record  the  number  of  the  sample  and  the  number  of  c.c.  of 
stannous  chloride  used. 

The  principles  upon  which  this  process  rests  are  as  follows: 
When  the  barium  chromate  is  added  in  excess,  it  reacts  with  the 
ammonium  sulphate  formed  from  the  combustion  of  the  gas  in 
an  ammoniacal  atmosphere,  in  the  following  manner: 

(NH4)2S04  +  BaCr04  =  BaSO4  +  (NH4)2CrO4. 

The  excess  of  barium  chromate  is  precipitated  by  ammonia  and 
filtered  out,  and  the  filtrate  then  contains  an  amount  of  ammonium 
chromate  equivalent  to  the  quantity  of  ammonium  sulphate 


TOTAL   SULPHUR  135 

originally  present.  The  boiling  is  to  remove  the  air  dissolved  or 
mechanically  contained  in  the  liquid,  which0  would  otherwise 
oxidize  the  stannous  chloride.  The  latter  reacte  with  the  ammo- 
nium bichromate  (formed  by  action  of  hydrochloric  acid  on 
ammonium  chromate)  to  form  stannic  chloride  and  chlorides  of 
ammonium  and  chromium: 

3  SnCl2  +  (NH4)2Cr2O7  +  14  HC1  =  3  SnCl4  +  2  NH4C1 
+  2  CrCl3  +  7  H2O. 

As  the  value  of  the  stannous  chloride  will  vary  from  day  to  day, 
especially  if  air  is  not  rigorously  excluded,  it  is  desirable  to  work 
out  a  factor  which  shall  take  this  into  consideration  and  which 
shall  simplify  the  calculation  of  results.  How  this  factor  is 
reached  will  be  made  clearer  by  a  specific  illustration.  The 
potassium  bichromate  contains,  say,  20.55  grams  to  the  liter, 
and  5  c.c.  of  this  are  equal  to  10  c.c.  of  the  stannous  chloride. 
In  titrating  the  sulphur,  4.75  c.c.  of  stannous  chloride  were  used. 

K2Cr2O7  :  3  SnCl2  :  :  (5  X  0.02055)  :  * 

x  =  0.1992  gram  of  stannous  chloride  in  10  c.c. 

0.1992  X  0.475  =  0.0946  gram  of  stannous  chloride  used  in 
titrating  the  sulphur  sample. 

Now  3  SnCl2  =  i  (NH4)2Cr2O7  -  2  (NH4)2SO4 

because     (NH4)2SO4  +  BaCrO4  =  BaSO4  +  (NH4)2CrO4 
and  2  (NH4)2Cr04  +  2  HC1  =  (NH4)2Cr2O7+  2  NH4C1  +  H2O; 
therefore  3  SnCl2  :  2  S  :  :  0.0946  :  x 

57°         64 
x  =  0.01062  gram  of  sulphur  in  0.8  foot  of  gas. 

0.01062  X  iS-43  X  100  .         £       .  .  ,  . 

— •-L-L2 =  20.48  grams  of  sulphur  in   100  cubic 

0.8 

feet  of  gas. 

Now  to  combine  these  equations  we  have 

5  X  0.02055  X  57°  X  4-75  X  64  X  15.43  X  100 
294  X  10  X  570  X  0.8 


136  GAS   AND   GAS   METERS 

of  which  the  570  in  numerator  and  denominator  cancel,  and  of 
the  rest  all  are  constant  quantities,  save  the  4.75,  the  10  and  the 
0.02055.  Eliminating  these  we  have 

5  X  64  X  15.43  X  IPO  = 

0.8  X  294 

Hence,  when  0.8  foot  of  gas  is  burned,  to  find  the  sulphur  in  grains 
per  hundred  cubic  feet,  multiply  the  grams  of  potassium  bichro- 
mate in  i  c.c.  by  2099.3  and  the  product  by  the  number  of  centi- 
meters of  stannous  chloride  used  in  titrating  the  sample,  and  divide 
by  the  number  of  cubic  centimeters  of  the  stannous  chloride  equiva- 
lent to  5  c.c.  of  the  potassium  bichromate.  If  a  number  of  analyses 
are  to  be  calculated  at  once,  it  will  save  time  if  a  slide  rule  or 
logarithm  table  be  used. 

This  method  has  been  repeatedly  checked  by  Major  Hinman, 
Mr.  Jenkins  and  the  writer,  against  the  standard  gravimetric 
process,  and  it  has  been  proved  beyond  a  doubt  to  be  accurate 
within  two  or  three  tenths  of  one  per  cent.  If  only  one  sample  is 
to  be  done  at  a  time,  it  is  no  more  rapid  than  some  of  the  methods 
already  mentioned;  but  if  a  number  of  analyses  are  to  be  made,  the 
saving  of  time  over  the  gravimetric  method  used  by  the  Referees 
is  very  great,  as  by  the  Hinman- Jenkins  method-  from  40  to  50 
determinations  can  be  made  in  a  day  by  one  man. 

One  of  the  greatest  difficulties  formerly  encountered  with  this 
process,  was  in  keeping  up  the  strength  of  the  stannous  chloride, 
since  any  contact  with  the  oxygen  of  the  air  causes  oxidation  to  set 
in.  This  has  been  entirely  overcome  by  the  use  of  an  apparatus 
devised  by  Mr.  Jenkins  and  copied  by  the  writer  in  his  laboratory. 
The  bottle  of  stannous  chloride  is  set  on  a  shelf  27  inches  from  the 
bench.  A  2-hole  rubber  stopper  is  wired  into  the  mouth  of  this 
bottle,  and  through  one  of  these  holes  a  glass  tube  passes  to  within 
one-half  inch  of  the  bottom  of  the  bottle,  and  above  the  stopper  it 
curves  and  passes  downward  to  connect  with  the  side  outlet  of  a 
Gavalowski  burette.  Through  the  other  hole  another  glass  tube 
passes,  reaching  one  inch  below  the  stopper,  and  connected  above 
to  the  outlet  of  the  carbonic  acid  generator.  The  top  of  the 
burette  is  closed  by  a  rubber  stopper  with  one  hole  through  which 


TOTAL   SULPHUR  137 

a  tube  projects  one-half  inch  into  the  burette  and  connects  above 
with  the  tube  leading  from  the  carbonic  acid  generator  to  the 
stannous  chloride  bottle. 

The  generator  is  home-made  and  consists  of  a  Mason  fruit  jar, 
filled  half  full  of  commercial  hydrochloric  acid.  Into  the  mouth 
of  this  jar  sets  a  large  rubber  stopper,  through  which  passes  a  piece 
of  an  adapter  12  inches  long,  3  inches  in  diameter  at  the  bottom, 
and  ij  inches  at  the  top.  The  tube  from  the  stannous  chloride 
passes  through  a  rubber  stopper  tightly  fitted  into  the  upper  and 
smaller  end,  while  the  lower  end  is  closed  by  another  stopper 
pierced  by  a  hole  three-sixteenths  of  an  inch  in  diameter.  Within 
this  adapter  are  placed  small  lumps  of  marble,  filling  it  to  a  height 
of  about  3  to  4  inches.  All  connections  are  wired  and  the  greatest 
precautions  taken  to  see  that  the  whole  apparatus  is  air  tight. 

When  the  cock  is  opened,  stannous  chloride  runs  into  the  burette 
and  in  so  doing  creates  a  vacuum  in  the  adapter.  This  causes  the 
acid  to  rise  through  the  hole  in  the  stopper  and  to  come  in  contact 
with  the  marble,  generating  carbonic  acid.  As  soon  as  the  burette 
is  full  the  cock  is  closed,  and  the  pressure  of  the  carbonic  acid 
generated  soon  forces  the  acid  back  into  the  Mason  jar.  Thus  the 
entire  outfit  is  filled  with  carbonic  acid,  and  air  never  comes  in 
contact  with  the  stannous  chloride.  The  Gavalowski  burette 
costs  about  $3.50,  but  aside  from  this  the  entire  apparatus  can  be 
made  in  the  laboratory. 

It  is  sometimes  desired  to  determine  the  carbon  bisulphide  in  gas 
by  itself.  For  this  the  method  of  Harding  and  Doran,  described 
in  the  Journal  of  the  American  Chemical  Society  Abstracts  for 
January  10,  1908,  may  be  used.  Briefly  described,  the  gas  is 
passed  from  the  meter  through  a  solution  of  caustic  potash  and 
then  through  concentrated  sulphuric  acid  to  remove  the  carbonic 
acid  and  water  vapor.  It  is  then  bubbled  through  a  solution  of 
caustic  potash  in  absolute  alcohol,  which  absorbs  carbon  bisul- 
phide, forming  potassium  xanthate  CS(OC2H5)SK.  The  xan- 
thate  solution  is  heated  to  expel  all  gases  and  acidified  with  acetic 
acid.  An  excess  of  a  standard  solution  of  cupric  acetate  is  added, 
resulting  in  the  formation  of  cupric  xanthate,  which  is  filtered  off 


138  GAS   AND   GAS   METERS 

and  washed  with  cold  water.  The  excess  of  cupric  acetate  in  the 
nitrate  is  determined  by  adding  potassium  iodide  and  titrating  the 
liberated  iodine  with  standard  sodium  thiosulphate,  using  fresh  starch 
solution  as  indicator.  This  method  has  been  successfully  tried  on 
the  gas  supplied  in  Minneapolis,  and  showed  the  presence  of  from 
12.60  to  14.16  grains  of  carbon  bisulphide  per  100  cubic  feet  of  gas. 

With  acetylene  the  determination  of  total  sulphur  is  of  little 
importance,  since  under  the  improved  conditions  of  carbide  manu- 
facture of  the  present  day,  impurities  have  been  largely  excluded 
from  the  acetylene.  Should  it  be  desired,  however,  to  make  such 
a  determination,  it  is  believed  that  the  Hinman- Jenkins  apparatus 
will  serve  admirably  for  the  collection  of  the  sample  in  liquid  form, 
if  two  changes  are  made.  First,  the  orifices  of  the  burner  and  the 
air-ports  must  be  adapted  to  acetylene  gas.  Second,  as  acetylene 
produces  but  little  water  on  combustion,  it  is  well  to  have  a  small 
continuous  stream  of  water  and  dilute  ammonia  playing  upon  the 
surface  of  the  beads.  As  this  liquid  runs  through,  it  may  be 
collected  in  a  large  flask  and  used  over  and  over,  so  that  the  total 
volume  of  the  sample  need  not  exceed  500  c.c.  The  analysis  must 
be  carried  out  by  a  different  process,  and  as  this  same  process  will 
include  the  determination  of  phosphorus,  arsenic  and  silicon,  it 
will  be  now  described  for  all  of  these  substances  at  once. 

The  solution  of  the  products  of  combustion  is  evaporated  twice 
to  dryness  with  nitric  acid,  the  residue  taken  up  in  water  and  nitric 
acid,  and  the  silica  filtered  off,  ignited  and  weighed.  The  filtrate 
is  evaporated  to  25  c.c.,  made  just  ammoniacal,  an  excess  of 
magnesia  mixture  is  added,  and  then  ammonia,  drop  by  drop, 
with  constant  stirring  until  one-third  of  the  total  solution  is 
ammonia.  This  will  precipitate  the  phosphorus  and  arsenic  as 
magnesium  ammonium  phosphate  and  magnesium  ammonium 
arsenate.  Let  stand  for  some  hours,  filter  off  the  precipitate  and 
wash  it  with  a  cold  mixture  of  one  part  ammonia,  one  part  alco- 
hol and  three  parts  water.  Evaporate  the  filtrate  to  dryness, 
acidify  with  hydrochloric  acid,  evaporate  again  to  dryness  and 
heat  until  the  ammonium  salts  are  expelled.  Take  up  in  water 
and  hydrochloric  acid,  heat  to  boiling,  add  a  hot  solution  of  barium 


TOTAL   SULPHUR  139 

chloride,  allow  the  precipitate  to  settle,  filter  off  the  barium  sul- 
phate and  ignite  and  weigh  it.  The  precipitate  of  magnesium 
ammonium  phosphate  and  arsenate  is  to  be  dissolved  in  hydro- 
chloric acid,  and  sulphuretted  hydrogen  passed  into  the  hot  solu- 
tion until  all  of  the  arsenic  is  precipitated  as  arsenious  sulphide. 
Filter,  and  wash  well  with  boiling  water.  This  precipitate  will 
always  contain  sulphur;  to  convert  it  to  pure  arsenious  sulphide 
extract  the  washed  and  still  moist  precipitate  on  the  filter 'with 
ammonia,  wash  the  residual  sulphur,  precipitate  the  solution  with 
hydrochloric  acid  without  heat,  filter,  dry,  extract  with  carbon 
bisulphide,  dry  at  100°  C.  and  weigh. 

The  filtrate  from  the  arsenious  sulphide  is  to  be  heated  to  expel 
the  sulphuretted  hydrogen,  the  phosphorus  precipitated  with  mag- 
nesia mixture  and  the  precipitate  washed  as  before.  Dry  the 
filter  and  contents,  ignite  in  a  porcelain  crucible,  and  weigh  as 
magnesium  pyrophosphate.  Great  care  must  be  taken  not  to 
reduce  the  magnesium  pyrophosphate  during  the  ignition;  to  this 
end  employ  a  low  heat  until  the  filter  paper  is  all  consumed, 
and  then  gradually  raise  the  temperature,  using  finally  the  whole 
heat  of  a  Tirrill  burner.  The  magnesia  mixture  employed  is 
made  by  dissolving  n  parts  of  crystallized  magnesium  chloride 
and  28  parts  of  ammonium  chloride  in  130  parts  of  water  and 
adding  70  parts  of  dilute  ammonia  (Sp.  Gr.  0.96).  Allow  the 
solution  to  stand  one  or  two  days  and  filter.  10  c.c.  of  this  is 
sufficient  for  o.i  gram  of  phosphoric  anhydride. 

On  account  of  the  small  percentage  of  these  impurities  usually 
present  in  acetylene,  it  is  necessary  to  burn  a  large  volume  of  the 
gas  in  securing  the  sample,  and  even  then  the  precipitates  will  be 
small  and  will  require  great  care  in  manipulation.  If  10  cubic 
feet  of  gas,  corrected  for  temperature  and  pressure,  are  taken,  the 
calculations  will  be  somewhat  as  follows :  Assume  weight  of  barium 
sulphate  0.2205  gram;  weight  Mg2P2O7,  0.0527  gram;  SiO2,  0.0172 
gram;  As2S3,  0.0052  gram. 

BaSO4  :  S  :  :   0.2205  :  x 

233        32 
x  =  0.0303  gram  of  sulphur  in  10  cubic  feet  of  gas. 


140  GAS   AND   GAS   METERS 

0.0303  X  15.43  X  10  =  4.68  grains  of  sulphur  per  100  cubic  feet. 
Mg2P2O7  :  P2  :  :  0.0527  :  x 

222  62 

x  =  0.0147  gram  of  phosphorus  in  10  cubic  feet  of  gas,  or  2.27 

grains  per  100  cubic  feet. 

SiO2  :  Si  :  :  0.0172  :  x 
60         28 
x  =  0.0080  gram  of  silicon  in  10  cubic  feet  of  gas,  or  1.23  grains 

per  100  cubic  feet. 

As2S3  :  As2  :  :  0.0052  :  x 
246        150 
x  =  0.0032  gram  of  arsenic  in  10  cubic  feet  of  gas,  or  0.49  grain 

per  100  cubic  feet. 

The  value  of  the  silicon  determination  by  this  method  is  doubt- 
ful. Glass  contains  silicon  as  one  of  its  most  important  constitu- 
ents, and  the  passage  of  the  water  and  salts  from  the  combustion 
over  the  glass  beads  and  through  glass  vessels  will  doubtless 
dissolve  a  small  amount  of  silica  therefrom.  It  is  therefore  better, 
if  silicon  alone  is  to  be  determined,  to  bubble  a  known  volume  of 
the  gas  through  a  solution  of  some  suitable  absorbent,  such  as 
caustic  potash,  and  then  separate  the  silica  from  this  by  the  usual 
method  of  dehydration. 

Eitner  and  Keppeler  burn  the  gas  at  the  rate  of  10  liters  per 
hour  (0.35  cubic  foot)  and  collect  the  products  of  combustion  in 
a  glass  hood,  from  which  they  are  aspirated  through  absorption 
bulbs.  The  first  ten  of  these  bulbs  contain  water;  a  second  set  of 
ten  contains  sodium  hypobromite,  and  these  are  followed  by  an 
empty  bulb  to  catch  any  spray  that  may  be  carried  over.  All  of 
the  phosphoric  acid  is  retained  in  the  glass  hood  and  first  set  of 
bulbs,  while  the  sodium  hypobromite  insures  the  retention  of  all 
of  the  sulphuric  acid. 

At  the  end  of  the  operation  the  glass  hood  is  inverted  and  filled 
with  hot  water  containing  hydrochloric  acid,  and  this  is  left  stand- 
ing over  night.  The  contents  are  then  concentrated  in  a  porce- 
lain dish  and  ammonium  carbonate  added.  Filter  off  the  silica 
and  so  forth,  and  add  the  filtrate  to  the  contents  and  washings  of 


TOTAL   SULPHUR 


141 


the  absorption  apparatus  after  they  have  been  boiled  with  hydro- 
chloric acid  to  destroy  the  hypobromite,  made  ammoniacal  and 
filtered.  After  cooling,  the  phosphoric  acid  is  determined  by 
precipitation  with  magnesia  mixture,  and  the  sulphuric  acid  in 
the  acidified  filtrate  from  this  determination  by  precipitation  with 
barium  chloride. 

This  is  one  of  the  best  methods  for  sulphur  and  phosphorus  in 
acetylene,  but  the  apparatus  is  so  cumbersome  that  it  will  not 
find  favor  in  any  but  well-equipped  laboratories.  It  also  takes 
no  account  of  the  silicon  and  arsenic,  and  the  latter,  if  present, 
would  probably  be  precipitated  with  the  phosphorus  and  thus 
render  the  results  for  that  substance  too  high. 

In  the  Journal  of  Gas  Lighting,  for  June  9,  1908,  the  follow- 
ing method  is  given:  "The  method  of  analysis  is  an  adaptation 
of  the  Referees'  sulphur  method,  modifying  the  burner  and  letting 
water  drop  through  the  column  while  the  gas  is  burning.  The 
water  solution  of  the  products  of  combustion  is  titrated  with 
N/io  soda  solution,  using  phenolphthalein  as  an  indicator.  The 
silica  is  then  dehydrated  and  weighed.  The  phosphoric  acid 
is  precipitated  from  the  silica  filtrate  with  magnesia  mixture,  and 
the  sulphuric  acid  in  the  filtrate  from  the  phosphoric  acid  by 
barium  chloride. " 

As  a  rule,  however,  the  quantitative  estimation  of  silicon,  phos- 
phorus or  arsenic  is  not  necessary,  since  undoubtedly  they  should 
not  be  allowed  in  the  gas  in  more  than  the  merest  traces,  and  a 
qualitative  test  will  therefore  give  all  the  information  necessary. 
Such  tests  have  already  been  given  for  sulphuretted  hydrogen  and 
for  phosphorus.  For  arsenic  a  modification  of  the  Marsh  test  may 
be  used,  provided  the  greatest  care  is  exercised  to  prevent  explosion. 

Lewes  states  the  amount  of  the  above  impurities  in  acetylene 
to  be  about  as  follows: 


Symbol. 

Maximum. 

Minimum. 

H2S 

i-34 

o.oo 

PH3 
SiH4 

1.70 
0.80 

o.  03 

0.  00 

AsH3 

o.  004 

0.  00 

142  GAS   AND   GAS   METERS 

The  silicon  and  phosphorus  are  objectionable  for  three  reasons. 
First,  they  are  poisonous;  second,  they  are  spontaneously  inflam- 
mable, and  if  present  in  sufficient  amount  will  ignite  the  acetylene; 
third,  their  products  of  combustion  clog  the  fine  orifices  of  the 
acetylene  burners.  Arsenic  is  of  course  dangerous  as  a  very 
violent  poison.  Lest  these  statements  should  produce  undue 
apprehension,  they  should  be  qualified  somewhat.  The  highest 
proportion  of  phosphoretted  hydrogen  ever  met  with  in  acetylene 
was  2.3  per  cent  (that  is,  in  acetylene  from  ordinary  carbide),  and 
this  gas  was  not  spontaneously  inflammable.1  Only  one  case  of 
spontaneous  inflammation  has  ever  been  recorded,  and  that  was 
in  the  earliest  years  of  carbide  manufacture.1 

Keppeler  says:  "When  generated  by  the  drip  system,  the  gas 
coming  from  a  carbide  containing  i  per  cent  of  calcium  phosphide 
catches  fire  of  itself,  whereas  if  the  carbide-to-water  system  be 
adopted,  25  per  cent  of  calcium  phosphide  is  needed  to  produce 
the  same  effect."1  It  should  also  be  stated  that  Wolff  could 
find  no  siliciuretted  hydrogen  or  arseniuretted  hydrogen  in  acety- 
lene. The  arsenic,  phosphorus  and  silicon,  if  present  at  all,  exist 
in  the  gas  as  AsH3,  PH3  and  SiH4  respectively,  and  burn  to  arsen- 
ious  oxide  and  arsenic  oxide,  phosphorus  pentoxide  and  silica. 
Arsenic  oxide  and  phosphorus  pentoxide  are  the  anhydrides  of 
arsenic  and  phosphoric  acids;  that  is,  if  they  combine  with  water 
they  form  the  above  mentioned  acids,  thus: 

As2O5  +  3  H,O  =  2  H3AsO4 

This  will  make  more  apparent  the  danger  resulting  from  their 
presence  in  gas. 

1  Scientific  American  Supplement,  August  8,  1903 


CHAPTER   III. 
OTHER  IMPURITIES. 

Ammonia.  In  coal  and  water  gases,  ammonia,  if  present,  is 
due  to  the  presence  of  nitrogen  in  the  coal  and  the  union  of  this 
nitrogen  with  hydrogen.  William  Foster,  after  studying  the 
distribution  of  the  nitrogen  of  coal  among  the  several  products 
of  destructive  distillation,  concluded  that  in  ordinary  gas  manu- 
facture, of  the  total  nitrogen  in  the  coal,  14.5  per  cent  is  evolved 
as  ammonia.  The  coal  on  which  he  conducted  his  experiments 
contained  1.73  per  cent  of  nitrogen,  and  as  a  general  thing  the 
amount  of  nitrogen  in  gas  coals  lies  between  i  and  2  per  cent.1 
E.  Schilling  reports  that  14  per  cent  of  the  total  nitrogen  is  the 
average  yield  as  ammonia,  and  20  per  cent  the  maximum  in  a 
number  of  experiments.  In  coke  ovens  C.  Winckler  found  that 
nearly  20  per  cent  of  the  nitrogen  of  coal  was  obtained  as  ammonia, 
while  Lewis  T.  Wright,  experimenting  with  Yorkshire  and  Derby- 
shire coals,  gives  the  percentage  of  nitrogen  recovered  as  ammonia 
as  from  22.3  to  23.6. 

These  figures  show  a  considerable  variation,  which  is  doubtless 
due  in  part  to  the  temperatures  of  distillation.  Wright  states 
that  the  yield  of  ammonia  is  greater  at  a  medium  than  at  a  high 
or  low  heat,  and  cites  figures  to  prove  the  point.  With  water 
gas,  the  amount  of  ammonia  formed  is  small,  due  to  the  fact  that 
the  temperature  at  which  ammonia  is  decomposed  is  below  that 
at  which  carbon  decomposes  steam. 

Now  this  ammonia  is  generally  removed  from  the  gas  for  two 
reasons :  first,  it  is  a  marketable  by-product,  and  the  revenue  from 
this  source  aids  in  reducing  the  cost  of  manufacture  of  the  gas; 
second,  ammonia  is  objectionable  in  the  finished  product  because 
(a)  it  acts  injuriously  on  the  meters  and  fixtures,  (b)  the  products 
of  its  combustion  may  become  deleterious  to  health  and  property, 

1  Butterfield's  Chemistry  of  Gas  Manufacture. 
143 


144  GAS   AND    GAS   METERS 

and  (c)  in  many  cases  there  is  a  legal  requirement  that  the  gas  as 
distributed  shall  not  contain  over  a  certain  quantity  of  ammonia. 

The  removal  of  the  ammonia  takes  place  first,  in  the  hydraulic 
main;  second,  in  the  condensers;  and  third,  in  the  washers  and 
scrubbers.  When  the  gas  leaves  the  retort,  it  contains,  among 
other  constituents,  ammonia,  carbonic  acid,  sulphuretted  hydrogen, 
and  certain  other  sulphur  compounds  of  an  acid  character,  such  as 
thiosulphuric  acid,  sulphocyanogen  and  so  forth.  The  ammonia, 
being  basic  in  character,  unites  to  some  extent  with  these  acid  radi- 
cals and  is  partly  carried  away  in  the  liquor  of  the  hydraulic  main. 
A  further  portion  is  taken  out  in  the  condensers,  where  the  aqueous 
vapor,  in  condensing,  carries  down  with  it  some  of  the  ammonia, 
sulphuretted  hydrogen  and  carbonic  acid  of  the  crude  gas.  Butter- 
field  considers  that  the  gas  from  common  coal,  after  condensation, 
but  prior  to  washing,  contains  between  0.5  and  0.95  per  cent  of 
ammonia  by  volume.  Practically  all  of  this  is  removed  in  a  well- 
managed  scrubber,  owing  to  the  great  solubility  of  ammonia  in 
water. 

It  not  infrequently  happens,  however,  that  ammonia,  and  to  a 
considerable  amount,  is  found  in  the  gas  after  it  has  passed  the 
washer.  This  may  be  due  to  several  causes.  First,  the  quantity 
of  water  used  may  be  insufficient;  second,  the  apparatus  may  be  so 
arranged  that  the  water  does  not  have  a  fair  chance  to  extract  the 
ammonia;  third,  the  water  may  have  taken  up  all  the  ammonia  that 
it  can  hold;  fourth,  on  passing  a  gas  practically  free  from  ammonia 
through  or  over  water  which  is  saturated  with  that  impurity,  the 
water,  far  from  taking  up  more  ammonia,  will  give  off  some  of  its 
original  content  to  the  gas,  and  this  process  will  be  continued  until 
an  equilibrium  is  reached.  This  is  also  true  when  small  quantities 
of  ammonia  are  involved.  As  soon  as  water  dissolves  any  ammonia 
it  becomes  a  solution,  and  is  ready  to  give  up  ammonia  to  any  gas 
containing  less  of  that  substance  than  it  carries  in  solution. 

For  this  reason  it  is  practically  impossible  to  furnish  coal  gas 
absolutely  free  from  ammonia,  although  the  amount  of  the  latter 
in  the  finished  product  may  be  cut  down  to  0.5  grain  or  less  per 
100  cubic  feet  of  gas. 


OTHER   IMPURITIES  145 

Another  point  that  is  worthy  of  attention  is  that  when  ammonia 
has  once  been  carried  beyond  the  washers  and  absorbed  in  purifiers, 
holder,  meters  or  drips,  it  will  be  given  up  again  when  a  gas  free 
from  ammonia  and  at  the  proper  temperature  passes  over  these 
storage  points.  The  writer  has  recently  met  with  a  curious  illus- 
tration of  this,  which  seems  worthy  of  repetition  in  the  light  of  an 
object  lesson.  A  plant  which  had  been  making  coal  gas  in  which 
ammonia  was  occasionally  allowed  to  pass  the  scrubbers,  suddenly 
changed  over  and  manufactured  water  gas.  Some  time  after, 
ammonia  was  found  in  the  gas  as  it  reached  the  consumer.  Know- 
ing that  water  gas  contains  little  or  no  ammonia,  the  manager  could 
not  account  for  this  phenomenon  and  was  inclined  to  lay  the  blame 
on  inaccuracy  in  testing  or  impurity  of  reagents.  As  the  proofs  of 
ammonia  multiplied,  however,  he  commenced  an  investigation,  and 
soon  found  that  the  ammonia  was  really  present  in  the  gas  and 
was  coming  from  the  purifiers  which  had  formerly  been  used  for 
coal  gas. 

The  detection  and  estimation  of  ammonia  in  gas  is  of  great  sim- 
plicity and  should  be  carried  out  in  every  coal-gas  works.  It  is  not 
necessary  that  a  chemist  should  be  employed,  as  the  necessary 
reagents  can  be  purchased  ready  for  use,  and  with  a  few  simple  pre- 
cautions the  test  may  be  made  with  sufficient  accuracy  by  any  intel- 
ligent and  careful  employee.  Three  methods  which  are  typical, 
accurate  and  in  general  use  will  be  described  in  detail ;  these  may  be 
designated  as  the  Massachusetts,  the  Referees'  and  Lacey  method. 

The  Massachusetts  method  is  the  one  employed  by  the  state 
inspectors  of  Massachusetts  and  New  York,  and  by  many  of  the 
gas  companies  in  those  districts.  The  apparatus  needed  consists 
simply  of  a  10  c.c.  pipette,  a  rubber  stopper  with  a  glass  tube  pro- 
jecting about  i  inch  on  either  side,  slightly  bent  and  drawn  out  to  a 
small  opening  on  the  lower  end,  and  a  bulb  similar  to  the  one  shown 
in  Fig.  20.  There  are  but  two  reagents  employed  in  the  actual  test, 
a  solution  of  cochineal  and  a  standard  solution  of  hydrochloric  acid ; 
while  to  standardize  the  latter,  a  solution  of  sodium  carbonate  and 
one  of  methyl  orange  are  needed. 

The  cochineal  solution  is  made  up  as  follows:    3  grams  of  the 


146  GAS  AND   GAS   METERS 

whole  cochineal  are  ground  in  a  porcelain  mortar,  transferred  to  a 
flask,  200  c.c.  of  water  and  50  c.c.  of  alcohol  are  added,  and  the 
whole  allowed  to  stand  for  48  hours  with  frequent  shakings.  At 
the  end  of  this  time  filter  off  the  residue  and  preserve  the  liquid  in  a 
glass-stoppered  bottle.  This  solution  will  keep  almost  indefinitely, 
and  as  only  2  to  3  drops  are  needed  for  each  determination,  the 
250  c.c.  as  prepared  above  will  answer  for  about  1000  tests. 


Fig.   20.     Ammonia  Bulb  and  Glass  Flower. 

The  standard  solution  of  hydrochloric  acid  is  made  of  such  a 
strength  that  i  c.c.  equals  o.ooi  grain  of  ammonia.  Other 
strengths  may  of  course  be  used,  but  the  above  figures  are  desir- 
able because  of  the  ease  of  calculation.  Now 

NH3   :HCl::i7  :  36.37  '•  :i  -2.14; 

therefore,  if  i  c.c.  of  the  standard  acid  is  to  equal  o.ooi  grain  of 
ammonia,  it  must  contain  2.14  grains  of  hydrochloric  acid. 
One  c.c.  of  N/io  hydrochloric  acid  contains  0.0561  grain  of  the 
acid.  2.14  divided  by  0.0561  equals  38.2.  Therefore  for  the 
desired  acid  it  is  only  necessary  to  take  38.2  c.c.  of  a  solution  of 
N/io  hydrochloric  acid  and  dilute  them  to  i  liter.  The  prepa- 
ration of  a  N/io  acid  solution  has  already  been  described  and 
need  not  be  repeated  here.  It  only  remains  then  to  standardize 
the  acid  used  for  the  ammonia  test. 

Make  up  a  solution  of  pure  sodium  carbonate  prepared  as 
before  described,  and  containing  0.2035  gram  to  the  liter. 
Place  this  solution  in  one  25  c.c.  burette,  and  the  acid  to 
be  tested  in  another.  Run  20  c.c.  of  the  alkali  into  a  porcelain 
dish,  add  two  drops  of  methyl  orange,  and  then  add  the  acid 
from  the  burette  until  the  color  of  the  solution  just  changes  from 


OTHER   IMPURITIES  147 

I 

yellow  to  red.  The  end-point  is  a  trifle  hard  to  judge,  owing  to 
the  extreme  dilution  of  the  solutions,  and  check  determinations 
should  be  made  until  the  operator  is  satisfied  with  the  accuracy 
of  his  results. 

Now  assume  that  20  c.c.  of  sodium  carbonate  have  required 
22.14  c.c.  of  the  hydrochloric  acid  for  neutralization, 

Na2CO3   :  2  HC1  :  :  (20  X  0.0002035)  :  x 

x  =  0.00280  gram  of  hydrochloric  acid  in  22.14  c-c-  Then  i  c.c. 
of  HC1  =  0.0001265  grams  HC1.  But  the  acid  desired  should 
contain  0.00214  grain,  or  0.00014  gram  to  i  c.c.  Conse- 
quently, to  make  the  acid  of  the  desired  strength,  it  is  necessary 
to  add  to  each  c.c.  (0.000140  —  0.0001265)  or  0.000013  gram 
HC1.  For  977.86  c.c.  (the  amount  remaining  after  the  first  titra- 
tion)  0.0127  gram  HC1  must  be  added.  The  N/io  HC1  con- 
tains 0.00364  gram  HC1  per  c.c.  0.0127  divided  by  0.00364 
equals  3.49  c.c.  This  amount  of  N/io  HC1  is  then  added  to  the 
977.86  c.c.,  the  mixture  well  shaken  and  the  titration  repeated. 
In  this  way  an  acid  is  speedily  obtained  which  is  near  enough  to 
the  theoretical  strength  to  be  well  within  the  limits  of  error  of 
the  process. 

To  conduct  a  test,  the  bulb  and  pipette  are  first  washed  out 
with  distilled  water  and  well  drained.  Suck  up  3  to  4  c.c.  of 
the  standard  acid  in  the  pipette,  and  shake  until  the  latter  has 
been  well  rinsed,  then  allow  the  pipette  to  drain  into  the  sink. 
Now  measure  out  exactly  10  c.c.  of  acid  with  the  pipette  and  let 
it  run  into  the  bulb.  Add  two  to  three  drops  of  the  cochineal  and 
insert  the  stopper.  Connect  the  glass  tube  with  the  gas  supply, 
and  the  outlet  of  the  bulb  with  the  inlet  of  a  meter  on  whose 
outlet  'a  burner  may  be  placed  to  consume  the  passing  gas. 

It  is  well  to  insert  a  small  glass  bulb  filled  with  cotton  wool 
between  the  acid  solution  and  the  meter,  in  order  to  prevent  any 
moisture  being  carried  over  into  the  latter.  The  cotton  must 
be  very  loosely  packed,  or  it  will  interfere  with  the  flow  of  the  gas. 

Now  pass  gas  through  the  solution  at  the  rate  of  0.6  to  0.8 
cubic  foot  per  hour,  and  note  the  reading  of  the  meter  at  the 
start.  As  soon  as  the  ammonia  in  the  gas  has  neutralized  the 


148  GAS   AND   GAS   METERS 

acid  in  the  bulb,  the  color  of  the  latter  will  change  from  a  yellow 
or  orange  to  a  deep  purple.  At  the  moment  when  this  change  of 
color  has  affected  the  entire  solution,  read  the  meter,  and  the 
test  is  finished.  The  acid  is  of  such  a  strength  that  if  this  change 
of  color  occurs  after  the  passage  of  i  cubic  foot  of  gas  (corrected 
as  usual),  the  latter  contains  exactly  one  grain  of  ammonia  per 
100  cubic  feet;  consequently  the  calculation  of  results  consists 
simply  in  correcting  the  volume  of  gas  burned  for  temperature 
and  pressure,  and  dividing  the  results  so  obtained  into  one;  the 
quotient  will  be  the  grains  of  ammonia  per  100  cubic  feet  of  gas. 

Two  or  three  precautions  and  suggestions  regarding  this  pro- 
cess should  be  noted.  The  standard  acid  is  very  dilute  and  thus 
extremely  susceptible  to  change  if  improperly  cared  for.  It 
must  never  be  left  exposed  to  the  air  for  even  a  few  moments;  it 
should  never  be  opened  in  a  room  where  the  fumes  of  ammonia 
have  recently  been  present;  none  of  the  acid  should  ever  be 
returned  to  the  bottle  after  once  having  been  taken  therefrom, 
and  the  part  of  the  stopper  which  enters  the  neck  of  the  bottle 
should  never  be  touched  or  placed  in  contact  with  any  object. 

In  case  the  gas  contains  much  sulphuretted  hydrogen,  the 
latter  will  dissolve  in  the  acid  and  so  interfere  with  the  test  for 
ammonia.  To  prevent  this,  Hempel  uses  a  bulb  containing  a 
solution  of  sugar  of  lead,  neutralized  with  acetic  acid,  and 
inserted  between  the  gas  supply  and  the  acid  solution.  If  there 
is  much  tar  in  the  gas,  a  small  bulb  filled  with  cotton  and  inserted 
in  front  of  the  standard  acid  will  catch  this.  The  meter  is  placed 
beyond  the  absorption  bulb,  as  otherwise  ammonia  might  be  taken 
up  or  given  off  during  the  passage  of  the  gas  through  the  meter. 

The  change  of  color  when  the  acid  is  neutralized  is  so  marked 
that  it  cannot  be  mistaken;  only  once  has  the  writer  seen  a  case 
where  the  end-point  might  have  caused  trouble.  In  this  instance, 
the  characteristic  color  change  took  place,  and  soon  after  the 
solution  lost  all  of  its  color  and  took  on  the  appearance  of  water. 
Addition  of  more  cochineal  reproduced  the  purple  color,  but  this 
was  again  decolorized  after  the  passage  of  a  little  more  of  the  gas. 
The  only  explanation  of  this  phenomenon  which  the  writer  can 


OTHER   IMPURITIES  149 

offer  is  that  the  gas  contained  sulphurous  acid  or  hydrocyanic 
acid  which  acted  on  the  cochineal  and  destroyed  the  color.  It 
should  be  added  that  the  gas  did  not  contain  any  sulphuretted 
hydrogen.  As  has  been  said,  however,  this  effect  has  been  seen 
but  once  out  of  many  thousands  of  tests  conducted  by  the  writer 
and  his  assistants,  and  if  the  acid  solution  is  watched  carefully 
from  start  to  finish,  no  inaccuracy  or  trouble  need  result  even  if  a 
repetition  of  this  occurrence  should  be  noted. 

This  process  is  usually  run  in  conjunction  with  the  determina- 
tion of  total  sulphur  by  the  Hinman- Jenkins  method,  the  acid 
bulb  being  inserted  in  the  series  between  the  gas  supply  and  the 
meter;  thus  the  two  operations  are  carried  out  at  one  and  the  same 
time  and  on  the  same  sample  of  gas.  The  method  is  simple, 
accurate  and  rapid,  and  the  cost  of  apparatus  and  reagents  is 
small.  The  bulb  for  the  standard  acid  costs  about  75  cents,  the 
pipette,  25  cents,  the  cochineal  solution  not  over  25  cents,  and  the 
standard  acid  may  be  purchased  of  any  reliable  chemist  at  a  price 
varying  with  the  amount  bought.  It  is  probable  that  enough 
could  be  purchased  for  $5  to  last  a  year,  since  it  costs  no  more  in 
time  or  material  to  make  up  10  liters  than  it  does  i  liter. 

The  London  Gas  Referees  no  longer  require  a  test  for  ammonia, 
but  their  former  directions  for  this  determination  are  as  follows: 
"Take  50  septems  (i  septem  equals  o.oooi  imperial  gallon  or 
7  grains  weight  of  pure  water  at  62°  F.)  of  the  test  acid  (which  is 
greatly  in  excess  of  any  quantity  of  ammonia  likely  to  be  found 
in  the  gas)  and  pour  it  into  the  glass  cylinder  or  saturator,  so  as 
to  well  wet  the  whole  interior  surface  and  also  the  glass  beads. 
Connect  i  terminal  tube  of  the  cylinder  with  the  gas  supply  and 
the  other  with  the  meter,  and  make  the  gas  pass  at  the  rate  of 
not  more  than  two-thirds  of  a  cubic  foot  per  hour.  Any  ammonia 
that  is  in  the  gas  will  be  arrested  by  the  sulphuric  acid,  and  a 
portion  of  the  acid  (varying  with  the  quantity  of  ammonia  in  the 
gas)  will  be  neutralized  thereby. 

"  At  the  end  of  each  period  of  testing  wash  out  the  glass  cylinder 
and  its  contents  with  distilled  water,  and  collect  the  washings  in 
a  glass  vessel.  Transfer  one-half  of  this  liquid  to  a  separate 


150  GAS  AND   GAS   METERS 

glass  vessel,  and  add  a  quantity  of  a  neutral  solution  of  litmus  or 
other  indicator  in  ordinary  use,  just  sufficient  to  color  the  liquid. 
Then  pour  into  the  burette  100  septems  of  the  test  alkali,  and 
gradually  drop  this  solution  into  the  measured  quantity  of  the 
washings,  stirring  constantly.  As  soon  as  the  color  changes  (indi- 
cating that  the  whole  of  the  sulphuric  acid  has  been  neutralized), 
read  off  the  quantity  of  liquid  remaining  in  the  burette. 

"  To  find  the  number  of  grains  of  ammonia  in  100  cubic  feet 
of  the  gas,  multiply  by  2  the  number  of  septems  of  test  alkali 
remaining  in  the  burette,  and  move  the  decimal  point  one  place 
to  the  left.1  It  should  be  stated  that  this  test  was  always  carried 
out  in  conjunction  with  the  test  for  total  sulphur,  and  conse- 
quently 10  cubic  feet  of  gas  were  always  used.  The  Referees' 
apparatus  for  these  two  tests  is  seen  in  Fig.  17,  A  being  the 
sulphur  apparatus,  B  the  meter,  C  the  aerorthometer,  D  the 
clock,  and  E  the  ammonia  cylinder  or  saturator. 

The  explanation  of  the  calculations  is  as  follows:  The  sul- 
phuric acid  is  made  of  such  a  strength  that  25  septems  contain 
enough  acid  (2.88  grains)  to  exactly  neutralize  i  grain  of  ammonia. 
The  standard  alkali  contains  i  grain  of  ammonia  in  each  100 
septems.  Now  assume  that  26.0  septems  of  alkali  remain  in  the 
burette  after  the  titration,  then  74.0  septems  were  exhausted  in 
neutralizing  the  excess  of  sulphuric  acid.  But  25  septems  of  the 
acid  equal  100  septems  of  the  alkali;  therefore  TVo  of  25  septems 
of  acid,  or  18.5  septems,  were  neutralized  by  the  ammonia  in  the 
gas,  and  6.5  septems  remained  for  reaction  with  the  standard 
alkali.  Then  since  only  one-half  of  the  sample  from  10  cubic 

feet  of  gas  was  titrated,  -^ ^^  =  5.2  grains  of  ammonia 

25  X  10 

per  100  cubic  feet  of  gas.  This  is  the  same  result  as  would  have 
been  reached  by  following  the  rule  given  above;  for  26  X  2  =  52, 
and  by  moving  the  point  one  place  to  the  left  we  get  5.2. 

Since  the  septem  as  a  unit  is  practically  unknown  in  the  scientific 
work  of  the  United  States,  and  since  nearly  if  not  quite  all  burettes 
and  pipettes  employed  here  are  graduated  in  cubic  centimeters, 
it  has  been  thought  advisable  to  state  the  values  of  the  solutions 

1  Abady's  Gas  Analyst  Manual. 


OTHER   IMPURITIES  I$I 

used  in  terms  of  the  metric  system.  The  ammonia  standard 
should  contain  1.4286  grams  of  ammonia  per  liter,  and  the  sul- 
phuric acid  16.471  grams  per  liter.  25  c.c.  of  acid  should  be 
taken  at  the  start,  and  100  c.c.  of  ammonia  used  in  the  burette. 
The  above  calculations  will  not  be  altered  by  this  change  of  nomen- 
clature, since  i  c.c.  of  the  acid  will  equal  4  c.c.  of  the  alkali,  and 
will  also  equal  0.04  grain  of  ammonia,  exactly  the  same  as  before. 
To  make  up  the  standard  acid,  proceed  as  follows :  pure  sulphuric 
acid  of  specific  gravity  1.839  *s  practically  100  per  cent  H2SO4; 
therefore  16.471  grams  would  be  (16.471  4-  1.839),  or  8-96  c.c. 
So  dilute  8.96  c.c.  of  the  pure  acid  to  i  liter.  To  standardize, 
precipitate  a  known  amount,  say  50  c.c.  or  100  c.c.,  with  barium 
chloride,  and  weigh  the  barium  sulphate  formed.  If  the  solution 
is  not  exactly  correct,  calculate  the  amount  of  water  or  acid  to 
add  in  order  to  make  it  so,  after  the  manner  shown  under  the 
Massachusetts  method.  The  ammonia  solution  is  made  by 
diluting  5.6  c.c.  of  pure  ammonia  (Sp.  Gr.  0.90)  to  i  liter  and 
standardizing  against  the  acid  of  known  strength. 

It  is  hard  to  see  why  litmus  is  mentioned  as  an  indicator.  It  is 
a  difficult  solution  to  prepare ;  it  does  not  keep  well  and  it  is  strongly 
affected  by  carbonic  acid  gas,  which  causes  the  red  color  to  persist 
even  though  the  liquid  be  alkaline,  and  thus  proves  a  source  of 
error.  If,  however,  litmus  is  to  be  used,  the  reader  should  con- 
sult Cohn's  Indicators  and  Test  Papers  for  the  method  of  prep- 
aration, the  precautions  to  be  observed,  the  accuracy  of  results,  etc. 

The  method  is  very  slow,  but  accurate  if  ordinary  care  is 
observed.  The  price  of  the  saturator  is  about  $2.50. 

Lacey's  method  is  especially  applicable  to  cases  where  it  is  neces- 
sary to  learn  as  quickly  as  possible  the  amount  of  ammonia  in 
the  gas.  The  apparatus  employed  is  shown  in  Fig.  21.  a  is  a 
modified  form  of  Wanklyn's  gas  bottle,  arranged  so  that  the  hand 
can  be  inserted  for  drying,  and  having  a  capacity  of  one-tenth 
cubic  foot,  the  hollow  stopper  being  made  with  a  flat  top  to  facili- 
tate handling,  b  is  a  25-septem  pipette,  and  c  an  alkalimeter  for 
measuring  the  ammonia  solution  during  the  titration  of  excess  acid. 

Two  solutions  are  used,  standard  sulphuric  acid  and  a  corre- 


152 


GAS  AND  GAS  METERS 


spending  solution  of  ammonia  of  known  value.  The  former 
may  be  made  by  diluting  one  part  of  the  ordinary  standard  acid 
solution  of  the  Referees'  test  with  99  parts  of  water;  25  sep terns 
of  this  solution  are  equivalent  to  o.oi  grain  of  ammonia.  In  a 
similar  manner  the  Referees'  ammonia  solution  is  diluted,  one 


IB 

•250 


15  -150 


Fig.  21.     Lacey's  Apparatus  for  Ammonia. 

part  to  99  parts  of  water,  to  make  the  standard  ammonia  used  in 
the  Lacey  test;  100  septems  of  this  diluted  solution  equal  o.oi 
grain  of  ammonia. 

In  making  a  test  the  gas  bottle  is  first  cleaned  and  thoroughly 
dried;  it  is  then  inverted  and  filled  with  the  gas  to  be  tested  by 
downward  displacement  of  the  air.  25  septems  of  the  acid  solu- 
tion are  measured  out  with  the  pipette  and  placed  in  the  hollow 
stopper,  together  with  two  drops  of  cochineal  solution.  With  the 
bottle  still  inverted  insert  the  stopper  and  shake  so  that  all  of  the 


OTHER   IMPURITIES  153 

inclosed  gas  shall  come  in  contact  with  the  reagents.  After  about 
two  to  three  minutes  empty  the  liquid  into  a  beaker  and  wash  out 
the  bottle  and  stopper  with  a  little  distilled  water,  adding  the 
washings  to  the  contents  of  the  beaker. 

Fill  the  alkalimeter  to  the  top  mark  with  the  ammonia  solution, 
place  the  thumb  over  the  larger  opening,  and  through  the  smaller 
one  allow  the  alkali  to  fall,  a  few  drops  at  a  time,  into  the  beaker, 
stirring  well  the  contents  of  the  latter.  Continue  the  addition  of 
the  alkali  until  the  orange  color  of  the  solution  changes  to  a  purple 
or  violet;  when  this  stage  is  reached,  set  the  alkalimeter  on  the 
table,  allow  it  to  drain  well,  and  from  the  quantity  of  alkali  remain- 
ing may  be  read  off  direct  the  grains  of  ammonia  per  100  cubic 
feet  of  gas.  Thus,  if  18  sep terns  remain,  since  each  of  these  is 
equivalent  to  o.i  grain  ammonia  per  100  cubic  feet  of  gas,  the 
gas  tested  contained  1.8  grains  of  ammonia  per  100  cubic  feet. 

Since  the  total  content  of  the  alkalimeter  is  only  100  septems, 
it  is  clear  that,  with  these  solutions,  determinations  cannot  be 
made  when  the  ammonia  in  the  gas  is  in  excess  of  10  grains  per 
ico  cubic  feet;  for  such  cases  either  the  solutions  may  be  made 
stronger,  or  50  c.c  of  acid  may  be  used.  In  titrating  the  excess 
of  acid,  when  50  c.c.  have  been  used,  it  must  be  remembered  that 
10  grains  or  the  equivalent  of  25  c.c.  of  acid  must  be  added  to  the 
result  when  calculated  in  the  ordinary  way.  In  unpurified  gas, 
it  is  better  to  make  the  solutions  of  greater  strength ;  Abady  recom- 
mends diluting  the  Referees'  ordinary  acid  solution  to  one-fourth 
its  strength,  and  using  the  same  ammonia  solution  as  is  used  by 
the  Referees  for  their  test  of  ammonia  in  purified  gas. 

This  method  is  an  excellent  one  for  works  use,  being  rapid,  fairly 
accurate,  and  easy  to  handle.  It  is  unfortunate  that  the  apparatus 
is  not  graduated  in  the  metric  system,  since  few  Americans  are 
familiar  with  septems  and  decigallons.  Still,  it  must  be  admitted 
that  the  calculations  are  simple  and  clear,  so  that  it  may  be  con- 
sidered that  the  practical  advantages  more  than  outweigh  the  theo- 
retical objections.  The  apparatus  necessary  for  this  process  costs, 
in  this  country,  approximately  $20. 

So  much  has  been  said  and  written  regarding  the  need,  or  need- 


154  GAS   AND    GAS   METERS 

lessness,  of  a  government  standard  for  sulphur,  ammonia  and  sul- 
phuretted hydrogen,  that  a  few  more  words  on  the  subject  may  not 
be  out  of  place  at  this  time.  The  opinion  seems  to  be  unanimous 
that  hydrogen  sulphide  should  practically  be  excluded  from  all 
illuminating  gas.  In  some  cases,  as  in  New  York  City  and  the 
State  of  Wisconsin,  the  requirements  are  that  only  a  trace  shall  be 
permitted,  but  the  great  objection  to  this  is  that  no  one  has  yet  given 
a  definition  of  a  trace  of  sulphuretted  hydrogen  which  would  enable 
the  authorities  to  enforce  the  law  by  an  appeal  to  the  courts,  if 
necessary.  The  writer  has  tested  gas  which  would  turn  lead  ace- 
tate paper  black  in  two  seconds,  and  yet  the  officers  of  the  company 
supplying  said  gas  insisted  that  only  a  trace  was  present.  It  seems 
to  be  the  better  practice  to-day  not  to  permit  even  a  trace  of  this 
impurity  in  the  gas  as  delivered  to  the  consumers,  and  as  a  rule 
there  is  very  little  complaint  against  this  regulation. 

With  regard  to  ammonia,  the  case  is  quite  different.  While  it  is 
true  that  its  presence  to  any  extent  in  the  gas  as  consumed  would 
be  deleterious  to  health  and  property,  it  is  also  true  that  it  practically 
never  occurs  to  such  an  amount  in  purified  gas.  Out  of  677  tests 
made  in  the  State  of  New  York  during  the  year  1908,  prior  to  Decem- 
ber i,  only  9  showed  the  presence  of  more  than  10  grains  of  ammo- 
nia per  100  cubic  feet  of  gas,  and  it  is  questionable  whether  even 
this  amount  would  be  dangerous.  The  limiting  of  the  quantity  of 
ammonia  which  may  be  present  in  gas  is  really  of  more  benefit  to 
the  gas  company  than  to  the  consumer,  since  this  ammonia  has  a 
commercial  value,  and  whatever  goes  into  the  gas  is  lost  to  the  com- 
pany; also  since  one  of  the  principal  evils  of  ammonia  is  the  effect 
It  has  upon  the  meters,  which  are  as  a  rule  the  property  of  the  gas 
company. 

It  seems  probable  for  these  reasons  that  the  gas  companies  will 
never  allow  much  ammonia  to  get  beyond  the  washers,  and  conse- 
quently it  is  difficult  to  perceive  the  need  of  any  governmental  regu- 
lation of  this  impurity.  The  test  for  ammonia  has  already  been 
abandoned  by  the  London  Gas  Referees,  and  the  Railroad  Com- 
mission of  Wisconsin  has  recently  decided  that  such  a  test  is 
unnecessary.  With  these  examples  to  follow,  it  is  possible  that 


OTHER   IMPURITIES  155 

restrictions  as  to  ammonia  will  form  an  unimportant  part  of  the 
gas  regulations  of  the  future. 

The  question  of  a  limit  for  total  sulphur  is  still  more  complicated. 
As  has  been  already  intimated,  the  restrictions  in  London  have  been 
removed,  and  now  there  is  considerable  complaint  that  the  action 
was  unwise,  as  the  gas  companies  have  taken  advantage  thereof  to 
furnish  gas  containing  30  and  even  40  grains  of  sulphur  per  100 
cubic  feet.  Massachusetts  still  holds  to  her  old  standard  of  20  grains 
per  100  cubic  feet,  although  there  is  an  agitation  in  that  state  at  the 
present  time  for  a  more  liberal  allowance.  New  York  likewise 
holds  to  20  grains,  while  Wisconsin  has  set  its  limit  as  30  grains. 

It  seems  to  be  the  consensus  of  opinion  in  the  best  informed  circles 
that  over  20  grains  of  sulphur  may  be  present  in  a  gas  without  ren- 
dering it  dangerous;  but  on  the  other  hand,  if  all  restrictions  are 
removed,  and  gas  containing  35  and  40  grains  of  sulphur  per  100 
cubic  feet  is  distributed,  there  is  liable  to  be  damage  to  health  and 
property.  Moreover,  the  supply  of  good  gas  coal  is  steadily  dimin- 
ishing, and  as  poorer  qualities  are  substituted,  the  percentage  of 
sulphur  is  likely  to  increase  rather  than  decrease.  Before  sulphur 
regulation  is  condemned  as  obsolete,  it  is  believed  that  further  in- 
vestigations are  needed  to  prove  definitely  whether  or  not  serious 
damage  would  result  from  the  presence  in  the  gas  of  30,  40,  or  50 
grains  of  total  sulphur. 

Naphthalene.  Naphthalene  can  hardly  be  classed  as  an  impurity, 
since  in  some  cases  it  is  employed  for  the  enrichment  of  gas  near  the 
burners;  but  it  is  nevertheless  often  one  of  the  disturbing  factors  in 
the  process  of  gas  manufacture  and  distribution.  It  is  formed  in 
the  retort,  along  with,  but  not  from,  benzene,  by  the  breaking  down 
of  the  hydrocarbons  of  the  paraffin  series,  and  the  polymerization 
of  the  products  of  such  decomposition.  Thus,  at  a  red  heat,  most 
methane  derivatives  will  yield  certain  amounts  of  benzene,  naphtha- 
lene, anthracene,  etc.,  while  the  higher  the  heats,  the  higher  will  be 
the  yield  of  naphthalene. 

Butterfield  says:1  "Actually,  naphthalene  in  a  state  of  vapor 
and  of  finely  divided  solid  is  usually  present  in  quantity  more 

1  Chemistry  of  Gas  Manufacture. 


i56 


GAS   AND   GAS   METERS 


than  sufficient  to  saturate  the  gas  with  naphthalene  vapor  at  the 
prevailing  temperature." 

Newbigging  says:1  "It  is  generally  believed  that  the  presence 
of  naphthalene  in  gas  is  due,  principally,  to  the  high  heats  neces- 
sarily used  in  the  carbonization  of  the  coal,  owing  to  the  partial 
distillation  of  a  portion  of  the  tar,"  and  goes  on  to  prove  this  by 
saying  that  in  the  days  of  iron  retorts,  when  the  heats  were 
necessarily  less  than  they  are  to-day  with  clay  retorts,  naphthalene 
as  now  found  in  the  mains  in  the  solid  state  was  almost  unknown. 

Now,  under  certain  conditions,  depending  on  various  factors 
such  as  the  richness  of  the  gas,  the  amount  of  aqueous  vapor 
which  it  carries,  the  speed  at  which  it  is  cooled,  etc.,  this  naph- 
thalene is  not  taken  out  in  condensers  and  scrubbers,  but  is 
carried  along  into  the  mains  and  distributing  pipes  and  there 
deposited,  causing  serious  trouble  through  the  obstruction  which 
it  offers  to  the  passage  of  the  gas.  Such  deposition  is  in  general 
due  to  three  causes:  (i)  Sudden  changes  of  temperature  of  the 
gas;  (2)  friction  in  the  pipes,  or  even  sharp  bends  in  the  latter; 
(3)  condensation  of  aqueous  vapor  from  the  gas  causes  depo- 
sition of  naphthalene. 

The  importance  of  the  first  cause  may  readily  be  seen  from  the 
following  table,  showing  the  vapor  pressure  of  naphthalene  and 
the  proportion  of  naphthalene  vapor  which  gas  can  retain  at 
varying  temperatures.2 


Temperature, 

Vapor    Press.,  mm. 

Vol.   Vapor  retained 

Degrees  Fahr. 

of  Mercury. 

by  TOO  vols.  Gas. 

32 

0.022 

o.  0029 

5° 

.047 

.0062 

59 

.  062 

.0082 

68 

.080 

.0105 

86 

•J35 

.0178 

104 

.320 

.0421 

140 

1.830 

.2410 

176 

7.400 

•9740 

212 

18.  500 

2.4300 

1  Handbook  for  Gas  Engineers  and  Manufacturers. 

2  J.  Soc.  Chem.  Ind.,  1900,  209,  by  R.  W.  Allen. 


OTHER   IMPURITIES  157 

Thus  if  ioo  volumes  of  gas  at  212°  F.,  containing  2.43  volumes 
of  naphthalene,  were  suddenly  cooled  to  32°  F.,  2.427  volumes 
of  the  naphthalene  would  be  dropped  out.  As  to  the  third  cause, 
Hornby  states  that1  .  .  .  "gas  absolutely  deprived,  as  far  as  pos- 
sible, of  aqueous  vapor  does  not  deposit  naphthalene  under  the 
ordinary  conditions  of  temperature  and  pressure, "  and  this  state- 
ment is  repeated  and  emphasized  in  Newbigging's  Handbook. 
Dr.  Harrop,  in  his  excellent  little  work  on  "  Gas  Works  Chem- 
istry," says:  "The  amount  of  naphthalene  made  is  a  question  of 
coal  and  retorting,  and  it  is  there  that  the  remedy  should  be  sought, 
but  a  high  naphthalene  gas  may  be  taken  care  of  in  the  con- 
densing system. 

.  .  .  Tf  the  gas  is  always  cooled  to  60°  F.  the  washers  and 
scrubbers  will  take  care  of  the  solid  flakes,  and  it  is  safe  to  rely 
on  25  grams  (or  actually  somewhat  less)  as  the  greatest  amount 
that  can  go  out  into  the  street.  If  this  is  seen  to,  and  supposing 
the  rest  of  the  condensing  operation  is  moderately  well  managed 
so  that  the  finished  gas  carries  a  fair  amount  of  condensible  hydro- 
carbons that  will  come  down  in  liquid  form  in  case  the  gas  hap- 
pens to  be  chilled  in  the  mains  or  service  pipes,  naphthalene 
troubles  will  be  rare." 

In  another  part  of  his  work,  under  the  head  of  Removal  of 
Tar,  he  says:  "The  problem  is  to  effect  a  cooling  that  will  make 
it  possible  to  extract  the  gaseous  ammonia,  to  remove  the  bulk  of 
the  naphthalene  vapor,  and  yet  to  leave  in  the  finished  product 
as  much  as  may  be  of  the  illuminant  vapors  of  those  hydro- 
carbons like  benzene,  which  condense  to  liquids  at  the  ordinary 
temperatures  of  the  street.  To  accomplish  this  it  is  believed  by 
most  engineers  that  a  cooling  by  successive  and  gradual  stages 
to  70°,  or  perhaps  60°  F.,  is  the  proper  course." 

Experiments  of  White  and  Barnes,  reviewed  in  the  Journal  of 
American  Chemical  Society  Abstracts,  January  i,  1907,  show  that 
incomplete  removal  of  tar  before  the  gas  reaches  the  scrubbers 
is  responsible  for  most  of  the  naphthalene  troubles  in  the  city 
mains;  that  the  tar  is  the  most  powerful  agent  in  the  removal  of 

1  Hornby,  Gas  Manufacture. 


158  GAS   AND   GAS 'METERS 

naphthalene,  and  that  if  the  former  is  removed  from  the  gas  by 
the  P.  &  A.  tar  extractor  at  the  proper  temperature,  little  or  no 
trouble  will  be  experienced  from  naphthalene. 

From  all  this  it  would  seem  that  prevention  is  a  far  better  and 
cheaper  policy  than  cure;  but  if  the  evil  has  occurred,  there  are 
various  methods  of  removing  it  which  do  not  enter  into  the  scope 
of  this  work,  but  which  may  be  said  in  general  to  depend  on  the 
extraction  of  the  naphthalene  by  various  solvents,  among  which 
naphtha  seems  to  have  played  the  most  important  part. 

There  is  only  one  test  of  any  importance  for  the  presence  and 
amount  of  naphthalene  in  gas.  This  is  known  as  Colman  and 
Smith's  test,  and  is  based  upon  the  fact  that  naphthalene  reacts 
with  picric  acid  to  form  naphthalene  picrate,  C10H8O  .  C6H2(NO2)3, 
which  is  almost  insoluble  in  aqueous  picric  acid.  For  a  qualitative 
test,  it  is  only  necessary  to  bubble  a  few  feet  of  the  gas  to  be 
examined  through  a  practically  saturated  solution  of  picric  acid, 
and  if  no  precipitate  forms,  the  absence  of  naphthalene  in  appre- 
ciable amount  may  be  asserted,  since  i  milligram  of  the  latter 
will  give  a  perceptible  precipitate. 

For  the  quantitative  determination,  3  reagents  are  required: 
(i)  a  standard  solution  of  picric  acid,  approximately  N/2O  (i.e., 
containing  about  22.9  grams  to  the  liter);  (2)  a  N/io  solution  of 
barium  hydrate;  (3)  a  solution  of  lacmoid.  The  picric  acid  is 
standardized  by  means  of  the  barium  hydrate,  using  the  lacmoid 
as  an  indicator.  The  color  of  the  solution  will  change  from 
brownish  yellow  to  green  when  the  picric  acid  has  all  been  neutra- 
lized and  the  alkali  is  in  excess. 

According  to  Button  the  barium  hydrate  is  made  up  as  follows: 
"  Shake  up  in  a  stoppered  bottle  powdered  crystals  of  barjum 
hydrate  with  distilled  water  and  allow  it  to  stand  a  day  or  two  until 
quite  clear;  there  should  be  an  excess  of  the  hydrate,  in  which  case 
the  clear  solution,  when  poured  off  into  a  stock  bottle  .  .  .  will 
be  nearly  twice  the  required  strength.  It  is  better  to  dilute  still 
further  (after  taking  its  approximate  strength  with  N/io  hydro- 
chloric acid  and  phenolphthalein)  with  freshly  boiled  and  cooled 
distilled  water;  the  actual  working  strength  may  be  checked  by 


OTHER   IMPURITIES  159 

evaporating  20  to  25  c.c.  to  dryness  with  a  slight  excess  of  sulphuric 
acid,  then  igniting  over  a  Bunsen  flame  and  weighing  the  barium 
sulphate." 

To  prepare  a  satisfactory  lacmoid  solution,  the  commercial  lac- 
moid  must  be  purified.  To  accomplish  this,  treat  the  fine  powder 
with  boiling  water,  acidulate  the  blue  solution,  after  cooling  and 
filtering,  with  hydrochloric  acid,  collect  the  precipitate  after  a  few 
hours,  wash  it  with  a  little  cold  water,  and  dry  at  not  too  high  a 
temperature.  To  prepare  the  indicator  solution,  take  3  grams  of 
the  purified  lacmoid  and  5  grams  of  naphthol  green  and  dissolve 
them  together  in  a  mixture  of  700  c.c.  of  water  and  300  c.c.  of 
alcohol.1  The  naphthol  green  is  added  to  counteract  the  violet 
tinge  which  is  generally  found  in  lacmoid  solutions,  however 
carefully  they  may  have  been  prepared,  and  which  is  very  liable 
to  deceive  the  observer. 

For  the  apparatus,  5  bottles  are  connected  in  series;  the  first  is 
of  4  ounces  capacity  and  contains  a  solution  of  citric  acid  to  remove 
any  ammonia  there  may  be  in  the  gas;  the  second  holds  10  ounces, 
and  contains  100  c.c.  of  the  picric  acid.  The  third  and  fourth 
contain  50  c.c.  each  of  the  same  solution,  while  the  fifth  serves  to 
retain  any  of  the  picric  acid  which  may  have  been  mechanically 
carried  over  from  the  other  bottles.  This  last  bottle  is  connected 
with  the  meter  inlet.  The  bottles  are  connected  one  with  the  other 
by  means  of  rubber  tubing,  as  close  a  joint  as  possible  being 
made,  and  the  pipe  from  the  first  bottle  to  the  gas  supply  being  of 
glass  (Fig.  22). 

The  ordinary  gas  pressure  is  not  sufficient  to  force  the  gas 
through  the  series  of  bottles  used  for  the  test,  and  so,  unless  the 
full  gas-holder  pressure  is  available,  it  will  be  necessary  to  increase 
the  pressure  by  means  of  either  a  water  jet  pump,  or,  better,  by 
Colman  and  Smith's  special  device,  which  is  shown  in  the  above 
cut,  and  which  is  described  as  follows: 

"The  method  consists  in  enclosing  the  meter2  in  a  stout  case  of 
galvanized  iron,  the  top  of  which  can  be  closed  air-tight  by  means 
of  suitable  clamps  and  packing  and  having  a  piece  of  plate  glass 

1  Cohn,  Indicators  and  Test  Papers. 

2  Abady,  Gas  Analysis  Manual. 


i6o 


GAS   AND   GAS   METERS 


fixed  in  the  front  to  allow  of  the  meter  index  being  read  off.  The 
inlet  of  the  meter  is  connected  by  means  of  a  union  to  tube  passing 
outside  the  meter  case,  which  is  connected  by  a  flexible  tube  to 
the  testing  apparatus,  the  outlet  of  the  meter  remaining  open. 
On  the  cover  are  3  tubes,  a,  b,  c,  and  a  fourth,  not  shown  in  the 
figure,  which  is  connected  to  the  mercury  pressure  gauge.  The 


Fig.  22.     Colman  and  Smith's  Naphthalene  Apparatus. 

tube,  a,  is  connected  to  a  small  steam  or  water  jet  vacuum  pump, 
and  b  and  c  to  the  pressure  regulator.  When  the  pump  is  started, 
and  the  air  drawn  from  the  meter  case,  the  mercury  level  rises  in 
the  right  hand  limb  of  the  U  tube,  B,  and  falls  in  the  left  limb, 
thus  continuing  until  the  level  in  the  latter  is  below  the  bottom  of 
the  tube,  C.  As  soon  as  this  occurs  air  is  drawn  into  the  meter- 
case  through  the  side  tube,  D,  and  the  vertical  tube,  C,  so  that  the 
vacuum  cannot  then  rise  higher. 

Any  desired  amount  of  vacuum  can  be  obtained  by  simply 
regulating  the  height  of  tube,  C,  and  so  long  as  the  pump  exhausts 
gas  more  quickly  than  it  passes  in  through  the  meter  or  through 
any  leaks  in  the  case,  this  vacuum  is  constantly  maintained.  The 
bottle,  E,  is  interposed  to  catch  any  globules  of  mercury  which  may 
be  carried  over  with  the  current  of  air. 

With  this  apparatus,  therefore,  the  pressure  around  the  meter 
can  readily  be  regulated  to  any  desired  amount  below  that  of  the 


OTHER   IMPURITIES  l6l 

atmosphere,  and  a  vacuum  of  2  inches  of  mercury  (27  in.  water) 
is  amply  sufficient  to  draw  the  gas  through  any  testing  apparatus, 
even  if  the  gas  itself  is  under  the  vacuum  of  12  inches  of 
water." 

In  making  the  usual  correction  of  the  volume  of  gas  registered  by 
the  meter  for  temperature  and  pressure,  the  amount  of  vacuum 
shown  on  the  mercury  pressure  gauge  must  be  deducted  from  the 
reading  of  the  barometer,  as  this  represents  the  difference  between 
the  atmospheric  pressure  and  that  within  the  meter  case.  The 
price  of  the  apparatus  delivered  in  this  country  will  be  in  the 
neighborhood  of  $65. 

In  carrying  out  the  process,  10  to  15  cubic  feet  of  gas  are  bubbled 
through  the  five  bottles  at  a  rate  of  from  0.5  to  i  cubic  foot  per  hour. 
When  the  necessary  quantity  of  gas  has  passed,  the  contents  of  the 
three  bottles  containing  picric  acid  are  combined  in  the  first  of  these 
bottles,  as  little  water  as  possible  being  used  for  rinsing. 

The  bottle  holding  the  solution  is  now  closed  by  a  rubber  stopper, 
through  which  passes  a  glass  tube  which  is  sealed  at  the  lower  end, 
but  having  a  small  hole  in  the  side  about  one  inch  from  the  bottom. 
This  tube  is  inserted  so  that  the  hole  is  just  below  the  bottom  of  the 
stopper,  and  the  air  removed  from  the  bottle  as  completely  as  possi- 
ble by  means  of  a  water  jet  pump.  While  the  latter  is  still  working, 
raise  the  tube  so  that  the  hole  shall  be  closed  by  the  stopper;  the 
bottle  is  thus  sealed  against  access  of  air. 

The  bottle  is  next  placed  in  a  water  bath  containing  sufficient 
water  to  cover  it,  and  the  temperature  in  the  bath  raised  to  the 
boiling-point  and  maintained  thus  until  the  liquid  in  the  bottle 
becomes  quite  clear.  Then  remove  the  bottle,  allow  it  to  cool, 
shaking  occasionally  to  wash  down  any  naphthalene  which  may 
solidify  in  the  upper  part  of  the  bottle.  Allow  the  solution  to  stand 
for  some  hours,  in  order  that  the  naphthalene  picrate  may  separate 
out  completely;  then  filter  with  aid  of  a  suction  and  wash  the  pre- 
cipitate with  a  small  amount  of  cold  water. 

Make  the  filtrate  and  washings  up  to  500  c.c.  and  take  100  c.c.  of 
this  for  titration  with  the  N/io  barium  hydrate.  The  washing  of 
the  precipitate  must  be  done  with  as  little  water  as  may  be,  for  the 


1 62  GAS  AND   GAS   METERS 

naphthalene  picrate,  while  almost  insoluble  in  picric  acid,  dissolves 
to  a  very  appreciable  extent  in  water. 

The  calculations  will  be  best  understood  by  citing  a  concrete 
instance.  10  cubic  feet  of  gas  were  used  for  the  test  and  40  c.c.  of 
the  N/io  barium  hydrate  were  required  to  neutralize  the  excess  of 
picric  acid,  i  c.c.  of  which  equals  0.52  c.c.  barium  hydrate. 

Ba(OH)2  :  2  C6H2(NO2)3OH  :  :  0.00855  :  *• 

i?1  458 

x  =  0.0229  grams  picric  acid  equivalent  to  i  c.c.  of  the  N/io 
Ba(OH)2. 

0.0229  X  °-52  =  0-01191  gram  picric  acid  per  cubic  centimeter  of 
that  solution. 

40  X  0.0229  =  0.9160  gram  picric  acid  uncombined  with  naphtha- 
lene. 

(0.01191  X  200)  —  0.9160  =  1.466  grams  picric  acid  combined 
with  naphthalene. 

C6H2(N02)3OH:C10H8   :  :  1.466  :  x. 

458  128 

x  =  0.4097  gram  naphthalene  per  10  feet  gas. 

0.4097  X  15.43  X  10  =  63.2  grams  naphthalene  per  100  feet. 

This  test  is  long,  cumbersome  and  inaccurate  if  the  details  are  not 
strictly  followed,  or  if  there  be  in  the  gas  any  hydrocarbon  with  a 
higher  boiling-point  than  that  of  naphthalene,  which  at  the  same 
time  forms  stable  picrates.  It  is,  however,  the  only  test  in  practical 
use,  and  in  experienced  hands  will  give  valuable  information. 

Hitherto,  tests  for  cyanogen  have  rarely  been  made,  but  with  the 
increase  of  plants  for  the  recovery  of  the  cyanides  in  gas,  this 
substance  becomes  of  importance  and  should  receive  brief  consid- 
eration. Foster  states  that  1.56  per  cent  of  the  nitrogen  in  coal  is 
converted  into  cyanogen  in  ordinary  gas  manufacture.  Butterfield 
considers  that  gas  from  common  coal  after  condensation,  but  prior 
to  washing,  contains  from  0.05  to  0.12  per  cent  by  volume  of  cyano- 
gen. He  believes  that  the  amount  of  cyanogen  will  depend  chiefly 
on  the  proportion  of  its  elements  in  the  coal  carbonized,  while 
Hornby  states  that  high  heats  will  produce  ten  times  as  much 


OTHER   IMPURITIES  163 

cyanogen  as  low  ones,  and  this  statement  is  borne  out  in  general  by 
Newbigging. 

The  cyanogen  exists  in  the  gas  principally  as  ammonium  cyanide, 
and  this  is  absorbed  to  a  considerable  extent  in  the  washers  and 
scrubbers.  Indeed,  it  may  be  entirely  removed  by  special  solutions, 
such  as  those  of  ferrous  salts,  placed  preferably  before  the  washers. 
Whatever  cyanide  passes  the  washers  is  partially  removed  by  the 
purifiers,  whether  of  lime  or  oxide,  with  this  difference  between  the 
two,  however;  the  lime  absorbs  the  cyanogen  more  completely,  but 
the  latter  cannot  be  recovered  therefrom;  while  the  oxide,  acting 
with  less  efficiency  as  an  absorbent,  yields  its  cyanogen  to  proper 
treatment. 

The  determination  of  cyanogen  may  be  made,  as  recommended 
by  Hempel,  by  absorbing  it  in  a  solution  of  caustic  potash,  adding 
silver  nitrate,  which  forms  the  insoluble  silver  cyanide,  and  then 
acidifying  slightly  with  nitric  acid.  The  silver  nitrate  forms  a 
heavy  white  precipitate,  which  may  be  filtered  off  and  ignited  in  a 
porcelain  crucible,  until  only  metallic  silver  remains.  From  the 
weight  of  the  latter  the  cyanogen  is  easily  calculated ;  thus,  if  10  cubic 
feet  gas  were  used  and  the  metallic  silver  weighed  1.3600  grams, 

Ag  :  CN  :  :  1.36  :  x. 
108     26 
x  =  0.3274  gram  cyanogen  in  10  cubic  feet  gas. 

0.3274  X  15.43  X  10  =  50.52  grains  cyanogen  per  100  cubic  feet 
gas. 

In  former  years  it  has  been  the  practice  in  some  localities  to  place 
a  restriction  on  the  amount  of  carbon  monoxide  which  should  be 
furnished  in  the  finished  product.  This  was  done  because  of  the 
undisputedly  poisonous  character  of  this  gas.  Of  late  years,  how- 
ever, it  has  come  to  be  generally  accepted  that  no  gas  is  made  to 
breathe,  and  the  growing  importance  of  the  water  gas  plants  in  this 
country  shows  how  little  attention  is  paid  at  the  present  time  to  the 
amount  of  carbon  monoxide  in  gas.  Should  it  be  necessary,  how- 
ever, to  test  for  this  substance,  a  regular  gas  analysis  outfit  should 
be  employed,  such  as  will  be  referred  to  in  the  following  chapter, 
where  this  determination  will  be  alluded  to  more  in  detail. 


CHAPTER  IV. 
THE  ANALYSIS  OF  GAS. 

To  cover  properly  the  subject  of  gas  analysis  would  require  a 
volume  by  itself.  Many  excellent  treatises  on  this  subject  are 
available,  notably,  Hempel's  Gas  Analysis,  and  for  detailed 
information  the  reader  is  referred  to  these.  It  is  not  the  purpose 
of  this  chapter  to  go  into  the  subject  exhaustively,  but  merely  to 
refer  to  the  general  principles  involved  and  to  a  few  of  the  more 
common  types  of  apparatus.  It  is  assumed  that  the  analyses  are 
to  be  made  by  a  trained  chemist,  and  consequently  the  subject 
will  be  treated  in  a  more  technical  manner  than  has  been  adopted 
for  the  preceding  tests,  which  in  many  cases  may  be  carried  out 
by  persons  not  possessing  a  thorough  chemical  education. 

In  general,  the  analysis  of  a  gas  consists  in  absorbing  the  con- 
stituents one  by  one  in  appropriate  reagents,  and  measuring  the 
decrease  in  volume  caused  by  such  absorption.  Certain  substances, 
such  as  hydrogen  and  methane,  cannot  be  readily  treated  in  this 
manner,  and  these  are  determined  by  exploding  with  oxygen  and 
determining  the  volume  of  the  products  of  explosion  or  the  diminu- 
tion in  volume  of  the  original  mixture. 

The  first  requisite  for  a  satisfactory  analysis  is  a  thoroughly 
representative  sample,  from  which  all  air  shall  have  been 
excluded.  A  simple,  accurate  and  economical  method  which  has 
been  in  use  for  many  years  by  the  Massachusetts  inspectors  is 
recommended  as  satisfying  every  requirement.  The  sample  tube 
(Fig.  23)  is  a  glass  bulb,  if  inches  diameter  and  2\  inches  long, 
with  the  ends  drawn  out  into  two  tubes  containing  capillaries  and 
terminating  in  two  short  ends  one-fourth  inch  in  diameter.  One 
end  is  connected  to  the  gas  supply  by  means  of  a  piece  of  pres- 
sure tubing;  the  gas  is  turned  on,  and  lighted  at  the  other  end  of 
the  sample  tube.  If  the  flame  is  not  over  ij  inches  long  there 

164 


THE   ANALYSIS    OF   GAS  165 

will  be  no  danger  of  melting  the  glass,  and  the  bulb  may  be 
purged  of  air  by  continuing  the  combustion  for  any  necessary 
period.  As  a  rule,  one-half  to  three-quarters  of  an  hour  will  be 
ample. 

When  the  sample  is  ready  for  sealing,  place  a  Mohr  pinch  cock 
on  the  inlet  tubing  and  turn  down  the  gas  until  the  flame  is  only 
one-fourth  to  three-eighths  inch  long.  With  a  blowpipe  seal 
the  capillary  nearest  the  outlet  first;  this  is  readily  done  by  hold- 


Fig.  23.     Sample  Tube. 

ing  the  sample  bulb  in  one  hand  and  the  end  of  the  tube  in  a  pair 
of  gas  pliers  held  in  the  other  hand;  as  soon  as  the  capillary  is 
white-hot  pull  the  two  hands  gently  apart,  keeping  the  blowpipe 
flame  playing  on  the  sealed  end.  With  the  gas  pressure  still  on, 
seal  the  other  capillary  in  a  similar  manner. 

To  transfer  the  sample  from  the  tube  to  a  eudiometer  or  pipette 
it  is  only  necessary  to  connect  the  two  with  a  piece  of  pressure 
tubing  of  glass  or  rubber,  filled  with  mercury,  and  join  the  other 
end  of  the  sample  tube  with  a  mercury  reservoir.  By  breaking 
the  sealed  capillaries  the  gas  may  be  readily  forced  from  the 
sample  tube  into  the  pipette.  The  sample  tubes  cost  but  fifty 
cents,  and  may  be  used  over  and  over  by  having  the  ends  again 
drawn  out  by  a  glass  blower. 

Having  secured  the  sample,  it  will  be  well  to  consider,  first, 
the  various  absorptions  and  explosions,  with  the  reagents  required, 
and  then  the  different  forms  of  apparatus.  For  the  absorption 
of  carbonic  acid,  caustic  potash  is  almost  universally  used,  either 
in  the  form  of  balls,  or  as  a  saturated  solution.  The  balls  are 
made  by  pouring  the  fused  caustic  into  a  bullet  mold,  and  must 
be  moistened  before  being  used  for  the  absorption  of  carbonic 
acid.  This  method  is  very  tedious,  and  is  not  to  be  recommended, 
as  the  use  of  solutions  is  fully  as  accurate  and  requires  only  three 


1 66  GAS   AND   GAS   METERS 

to  four  minutes.  The  potash  for  such  solution  should  be  pure, 
but  the  variety  known  as  " purified  by  alcohol"  must  not  be  used. 
The  reagent  must  be  kept  from  contact  with  the  air,  or  it  will 
deteriorate  rapidly. 

Dr.  Harrop  suggests  the  use  of  caustic  soda  in  place  of  caustic 
potash,  but  it  is  a  little  difficult  to  see  the  reason  for  this.  The 
former  is  cheaper,  it  is  true,  but  the  latter  is  the  better  reagent, 
and  is  recommended  by  Hempel,  Sutton,  Crookes,  Fresenius, 
Hinman,  Jenkins  and  others.  According  to  Hempel  i  c.c.  of 
caustic  potash  (i  part  caustic  potash  to  2  parts  of  water)  has  an 
analytical  absorbing  power  of  40  c.c.  carbonic  acid.  He  also 
shows  that  when  the  percentage  of  carbonic  acid  is  not  too  high, 
it  can  be  completely  absorbed  by  simply  passing  the  gas  once 
into  the  pipette,  the  entire  manipulation  taking  less  than  one  minute. 

In  case  there  is  any  doubt  whether  all  of  the  carbonic  acid  has 
been  removed,  the  gas  should  be  passed  two  or  more  times  into 
the  absorption  pipette,  until  there  is  no  further  diminution  in  the 
volume  of  the  sample.  For  very  small  amounts  of  carbonic  acid, 
it  is  better  to  absorb  in  a  solution  of  barium  hydrate  and  titrate 
the  excess  of  the  latter  with  standard  oxalic  acid  solution. 

Four  reagents  have  been  extensively  used  for  the  absorption  of 
oxygen,  namely,  phosphorus,  pyrogallic  acid,  chromous  chloride, 
and  metallic  copper.  The  first  is  employed  in  the  form  of  a  long, 
moist  stick,  and  removes  the  oxygen  through  formation  of  phos- 
phorous acid,  which  dissolves  in  the  water.  The  absorption  takes 
about  an  hour,  according  to  Crookes,  and  it  is  supposed  to  be 
complete  when  white  fumes  no  longer  appear  on  the  stick  of 
phosphorus.  Hempel  considers  that  after  three  minutes,  at  the 
longest,  the  absorption  is  complete,  and  the  end  point  is  sharply 
shown  by  the  disappearance  of  the  glow  which  normally  attends 
the  reaction;  this  glow  can  best  be  observed  in  a  dark  room.  At 
10°  C.,  or  lower,  the  reaction  will  not  be  complete  in  a  half-hour's 
time. 

This  process,  known  as  the  Lindeman,  is  one  of  the  finest  methods 
of  gas  analysis,  but  is  only  applicable  under  certain  conditions. 
Schonbein  has  shown  that  the  reaction  is  wholly  or  partly  pre- 


THE   ANALYSIS   OF   GAS  1 67 

vented  by  the  presence  of  ethylene  and  other  hydrocarbons  or 
ethereal  oils,  by  traces  of  ammonia,  etc.;  and  as  these  compounds 
are  always  liable  to  be  present  in  illuminating  gas,  the  results 
obtained  by  the  use  of  phosphorus  in  the  analysis  of  such  gases 
are  of  doubtful  value.  In  addition  to  this,  it  is  difficult  to  free  the 
gas  from  phosphorous  acid;  the  latter  exerts  some  tension  and  so 
vitiates  the  results.  If  phosphorus  is  employed,  however,  it  must 
be  kept  from  the  light,  in  which  case  it  is  capable  of  absorbing  an 
enormous  quantity  of  oxygen. 

An  alkaline  solution  of  pyrogallic  acid  is  the  favorite  reagent 
to-day  for  the  absorption  of  oxygen.  Dr.  Harrop  recommends 
that  15  grams  of  pyrogallol  be  dissolved  in  a  small  quantity  of 
water  and  introduced  into  the  pipette,  which  is  then  filled  with  a 
solution  of  caustic  soda  of  the  same  strength  as  that  used  in  the 
carbonic  acid  pipette.  Hempel  prepares  the  solution  by  dissolving 
5  grams  of  pyrogallol  in  15  c.c.  of  water,  and  adding,  after  this  is 
in  the  pipette,  120  grams  of  caustic  potash  dissolved  in  80  c.c.  of 
water.  Sutton  saturates  a  ball  of  papier-mache  with  the  solution, 
and  uses  this  ball  in  the  absorbing  vessel,  but  this  is  not  as  satis- 
factory as  the  use  of  the  solution  itself,  on  account  of  the  smaller 
surface  exposed  to  the  action  of  the  gas,  and  the  lesser  amount  of 
reagent  present. 

At  a  temperature  of  15°  C.,  or  higher,  the  last  trace  of  oxygen 
can  be  removed  with  certainty  in  the  space  of  three  minutes  by 
shaking  with  the  solution  of  alkaline  pyrogallol ; l  it  will  be  found 
safer,  however,  to  allow  the  gas  to  stand  in  contact  with  the  reagent 
for  15  to  20  minutes,  with  frequent  shakings.  The  solution  must 
be  kept  strictly  from  contact  with  the  air,  or  it  will  deteriorate 
rapidly;  i  c.c.  of  fresh  reagent  will  absorb  from  8  to  9  c.c.  oxygen. 
When  first  made  the  solution  should  be  light  yellow,  and  should 
turn  red  on  contact  with  oxygen. 

The  advantage  of  chromous  chloride  as  an  absorbent  for  oxygen 

lies  in  the  fact  that  it  may  be  used  in  the  presence  of  carbonic  acid 

or  sulphuretted  hydrogen,  being  the  only  reagent  that  will  absorb 

oxygen  alone  from  a  mixture  of  oxygen  and  sulphuretted  hydrogen. 

1  Hempel,  Gas  Analysis. 


1 68  GAS   AND   GAS   METERS 

Moissan's  method  for  the  preparation  of  chromous  chloride  is  as 
follows  i1  A  green  solution  of  chromium  chloride  free  from  chlorine 
is  made  by  heating  chromic  acid  with  concentrated  hydrochloric 
acid,  and  this  solution  is  then  reduced  with  zinc  and  hydrochloric 
acid.  Since  spongy  particles  always  separate  from  the  zinc  used 
in  the  reduction,  the  solution  must  be  filtered.  For  this  purpose 
the  reduction  is  carried  on  in  a  flask  fitted  with  a  long  and  a  short 
tube,  as  is  a  wash  bottle.  The  longer  tube  is  bent  downward  above 
the  flask  and  is  here  supplied  with  a  small  bulb  tube,  which  is 
filled  with  glass  wool  or  asbestos. 

The  hydrogen  given  off  during  the  reduction  is  allowed  to  pass 
out  through  the  longer  tube  for  some  time;  then  after  closing  its 
outer  end  the  tube  is  pushed  down  into  the  solution.  The  hydro- 
gen is  thus  obliged  to  pass  out  through  the  shorter  tube,  which 
carries  a  rubber  valve. 

Carbonic  acid  is  then  passed  into  the  flask  through  the  short 
tube,  and  the  chromous  chloride  solution  is  driven  over  into  a 
beaker  containing  a  saturated  solution  of  sodium  acetate.  A 
red  precipitate  of  chromium  acetate  is  formed  which  is  washed 
by  decantation  with  water  containing  carbonic  acid.  The  red 
chromium  acetate  is,  relatively  speaking,  quite  unchangeable,  and 
in  moist  condition  it  may  be  kept  for  an  unlimited  time  in  closed 
bottles  filled  with  carbonic  acid. 

In  washing  the  red  precipitate,  some  free  acetic  acid  is  added  in 
the  beginning,  to  dissolve  any  basic  zinc  carbonate  which  may 
have  been  thrown  down.  In  this  way  a  preparation  completely 
free  from  zinc  is  obtained. 

To  absorb  oxygen,  the  chromium  acetate  is  decomposed  by  the 
addition  of  hydrochloric  acid,  the  air  being  excluded.  It  is  advis- 
able to  use  an  excess  of  chromium  acetate  in  order  to  avoid  the 
presence  of  free  hydrochloric  acid.  This  reagent  seems  to  be  but 
little  used,  probably  because  of  the  difficulty  of  its  preparation,  and 
because  it  is  seldom  required  to  determine  oxygen  in  the  presence  of 
sulphuretted  hydrogen  or  carbonic  acid;  it  is  not  as  highly  recom- 
mended as  either  the  phosphorus  or  the  alkaline  pyrogallol. 

1  Hempel,  Gas  Analysis. 


THE   ANALYSIS   OF   GAS  169 

Copper  is  practically  never  used  for  the  determination  of  oxygen 
in  illuminating  gas,  for  the  reason  that,  in  the  form  in  which  it  is 
employed,  namely,  little  rolls  of  wire  gauze  immersed  in  a  solution 
of  ammonia  and  ammonium  carbonate,  basic  ammonium  cuprous 
carbonate  is  formed,  which  absorbs  carbon  monoxide.  If  the 
latter  gas  be  absent,  as  is  sometimes  the  case  with  petroleum  and 
naphtha  gases,  and  is  indeed  very  often  true  of  natural  gas,  this 
method  would  seem  to  be  excellent.  The  copper  has  a  much 
greater  absorbing  power  for  oxygen  than  alkaline  pyrogallol,  while 
it  has  the  advantage  over  phosphorus  of  absorbing  equally  well 
at  all  temperatures. 

Of  the  four  reagents  mentioned,  the  alkaline  pyrogallol  is  the 
most  satisfactory  for  use  with  illuminating  gas.  Attention  must, 
however,  be  paid  to  the  fact  that  it  deteriorates  rapidly,  and  fresh 
portions  should  be  employed  at  frequent  intervals. 

In  the  Journal  of  the  American  Chemical  Society,  March,  1908, 
Franzen  proposed  the  use  of  sodium  hydrosulphite  for  absorption 
of  oxygen,  one  gram  of  reagent  absorbing  64  c.c.  of  the  gas, 
Na2S2O4  +  H2O  +  O  =  2  NaHSO3.  Fifty  grams  of  the  hydro- 
sulphite  are  dissolved  in  250  c.c.  water  and  40  c.c.  caustic  soda 
solution  (500  grams  in  700  c.c.  water),  and  the  solution  used  in  a 
Hempel  pipette  for  solid  substances  filled  with  iron  wire  gauze. 
One  cubic  centimeter  of  this  solution  absorbs  10.7  c.c.  oxygen.  It 
is  cheaper  than  pyrogallol,  it  may  be  used  in  weakly  alkaline  solu- 
tion, and  has  the  same  absorptive  power  at  various  temperatures;  it 
may  be  used  with  gases  containing  carbon  monoxide,  and  at  lower 
temperatures  and  in  presence  of  substances  that  hinder  the  oxida- 
tion of  phosphorus.  This  reagent  has  not  yet  been  sufficiently 
tried  to  recommend  its  adoption,  but  in  view  of  the  advantages 
above  stated,  it  is  certainly  worthy  of  careful  consideration. 

Carbon  Monoxide.  If  carbon  monoxide  is  to  be  determined  by 
absorption,  but  two  reagents  need  to  be  considered ;  a  hydrochloric 
acid  solution  of  cuprous  chloride,  or  an  ammoniacal  solution  of 
the  same.  Abady  considers  that  the  action  of  the  latter  is  sharper, 
but  that  the  former  is  less  troublesome  to  make.  There  are  several 
points  to  be  noted  in  connection  with  the  use  of  either  of  these 


I/O  GAS   AND   GAS   METERS 

reagents.  If,  after  the  absorption  of  carbon  monoxide,  the  hydro- 
gen is  to  be  determined  with  palladium,  the  ammoniacal  solution 
must  be  used. 

The  solutions  of  cuprous  chloride  are  absorbents  not  only  for 
carbon  monoxide,  but  also  for  acetylene  and  ethylene;  if  this  fact 
is  not  remembered,  the  results  may  be  entirely  valueless.  More- 
over, certain  gases  not  absorbable  by  cuprous  chloride  are  much 
more  soluble  in  this  than  in  other  absorbing  liquids;  therefore,  to 
obtain  accurate  results  a  cuprous  chloride  solution  which  has  been 
saturated  with  the  gases  ,but  slightly  soluble  in  it  must  unques- 
tionably be  used.1 

Experiments  have  also  shown  that  even  when  the  heavy  hydro- 
carbons are  not  to  be  determined,  they  must  be  removed  before 
the  carbon  monoxide  is  absorbed  by  the  cuprous  chloride.  Last, 
but  not  least,  Drehschmidt  has  demonstrated  that  the  union  of 
carbon  monoxide  with  cuprous  chloride  is  so  feeble  that  upon  shak- 
ing a  solution  that  has  taken  up  any  considerable  quantity  of 
carbon  monoxide,  this  latter  is  again  given  up  in  an  atmosphere 
free  from  that  gas.  It  is  therefore  necessary  to  employ  two 
pipettes,  the  first  containing  a  solution  of  cuprous  chloride  that  has 
been  used  many  times,  and  the  other  a  solution  that  is  practically 
fresh. 

If,  in  spite  of  these  facts,  it  is  desired  to  use  the  cuprous  chloride 
solution,  it  may  be  prepared,  according  to  Dr.  Harrop,  in  the 
following  manner:  "A  liberal  supply  of  copper  wire  is  put  into  a 
pint  stoppered  bottle,  one  part  water  is  added  to  two  parts  concen- 
trated hydrochloric  acid,  and  in  this  diluted  acid  crystallized 
cuprous  chloride  is  dissolved  to  saturation.  The  solution  is 
poured  into  the  bottle  and  allowed  to  stand  for  several  days,  or 
until  the  solution  is  reduced,  as  shown  by  becoming  almost  color- 
less. The  pipette  may  then  be  filled  with  the  clear  solution.  The 
absorption  of  carbon  monoxide  is  not  very  active,  and  the  charge 
in  the  pipette  must  be  frequently  renewed." 

Sandmeyer  prepared  the  hydrochloric  acid  solution  thus: 
"  25  parts  of  crystallized  copper  sulphate  and  12  parts  of  dry 

1  Hempel,  Gas  Analysis. 


THE   ANALYSIS    OF   GAS  1 7 1 

sodium  chloride  are  placed  in  50  parts  water  and  heated  until 
the  copper  sulphate  dissolves.  Some  sodium  sulphate  may 
separate  out  at  this  point,  but  the  preparation  is  continued  with- 
out the  removal  of  this  salt.  One  hundred  parts  of  concen- 
trated hydrochloric  acid  and  13  parts  of  copper  turnings  are  then 
added,  and  the  whole  is  boiled  in  a  flask  until  decolorized.  To 
avoid  excessive  evaporation  it  is  desirable  to  insert  in  the  neck  of 
the  flask  a  tall  condensing  tube  or  an  upright  condenser.  The 
addition  of  platinum  foil  to  the  contents  of  the  flask  will  facili- 
tate reduction.  The  solution  should  be  kept  in  bottles,  which  are 
filled  up  to  the  neck  and  are  closed  by  rubber  stoppers."  1 

For  the  preparation  of  the  ammoniacal  cuprous  chloride, 
Hempel  recommends  the  following  procedure:  1500  c.c.  of  the 
Sandmeyer  solution  is  poured  into  about  5  liters  of  water,  and 
the  resulting  precipitate  is  transferred  to  a  stoppered  measuring 
cylinder  containing  about  320  c.c.,  and  upon  which  there  has  been 
previously  marked  the  height  at  which  62  c.c.  of  liquid  would 
stand.  After  about  two  hours  the  precipitate  and  liquid  which 
are  above  this  62  c.c.  mark  are  drawn  off  by  means  of  a  syphon,  and 
7.5  per  cent  ammonia  is  added  up  to  320  c.c.  mark,  that  is,  to 
the  top  of  the  cylinder.  The  stopper  is  inserted,  the  cylinder  is 
well  shaken,  and  it  is  then  allowed  to  stand  for  several  hours.  A 
solution  prepared  in  this  manner  has  so  slight  a  tension  that  the 
latter  may  in  nearly  every  case  be  neglected. 

In  view  of  the  difficulties  attending  the  absorption  of  carbon 
monoxide  by  cuprous  chloride,  it  has  become  the  custom  with 
many  analysts  to  determine  this  constituent  by  explosion  with 
oxygen,  and  this  method  would  seem^to  be  both  easier  and  more 
accurate.  Gautier  and  Clausman,  however,  in  a  recent  article 
state  that  in  a  mixture  of  nitrogen  or  air  and  carbon  monoxide, 
or  of  nitrogen  with  different  combustible  gases  and  carbon  mon- 
oxide, the  latter  cannot  be  accurately  determined  either  by 
explosion  with  oxygen  or  by  treatment  with  cuprous  chloride; 
but  if  the  gas  after  the  explosion  or  after  treating  with  cuprous 
chloride  is  passed  over  iodine  pentoxide  heated  to  70  degrees, 

1  Berichte  der  deutschen  chemischen  Gesellschaft  17,  1633. 


172  GAS   AND   GAS   METERS 

the  last  trace  of  carbon  monoxide  will  be  oxidized.  The  writer 
has  been  unable  to  verify  this  and  merely  gives  the  statement  in 
order  that  it  may  be  thoroughly  investigated. 

Illuminants.  Sutton  states  that  the  hydrocarbons  (CnH2n+1)2 
and  CnH2n+2  may  be  absorbed  by  absolute  alcohol.  The 
method,  however,  gives  but  approximate  results  and  can  be 
employed  only  in  the  presence  of  gases  very  slightly  soluble  in 
alcohol.  Hempel  states  that  Bunsen  made  use  of  absolute 
alcohol  to  determine  the  gaseous  hydrocarbons  that  are  not 
properly  gases  in  purified  illuminating  gas,  and  found  that  the 
hydrocarbons  thus  absorbed  consisted  chiefly  of  benzene. 

While  bromine  has  in  the  past  been  used  for  the  absorption  of 
the  illuminants  in  gas,  the  reagent  most  frequently  employed  for 
that  purpose  to-day  is  Nordhausen,  or  fuming  sulphuric  acid. 
This  does  not  absorb  methane  but  takes  up  principally  ethylene, 
propylene  and  benzene. 

The  use  of  Nordhausen  acid  naturally  forbids  the  presence  of 
water,  and  the  absorption  pipette  must  be  thoroughly  dried 
before  use.  If  mercury  is  to  be  the  confining  fluid,  some  trouble 
may  be  experienced  through  the  fact  that  fuming  sulphuric  acid 
acts  quite  energetically  on  that  element,  in  presence  of  minute 
traces  of  water  vapor,  and  forms  a  solid  mass  which  obstructs 
the  passage  of  the  gas.  This  may  be  prevented  by  diluting  one 
part  of  the  Nordhausen  acid  with  one  part  of  concentrated  sul- 
phuric acid,  specific  gravity  1.84,  and  cooling  the  mixture  before 
use.  The  absorption,  of  the  illuminants  is  rather  slow,  and  at 
least  an  hour  should  elapse  before  the  action  is  considered  com- 
plete. It  is  then  always  necessary  to  pass  the  gas  into  a  caustic 
potash  pipette  in  order  to  absorb  any  sulphurous  acid  which  may 
have  been  carried  over  by  the  gas. 

Benzene.  In  the  absorption  of  this  constituent  Dr.  Harrop 
employs  an  ammoniacal  solution  of  nickel  hydrate.  This 
method  was  severely  attacked  by  D.  A.  Morton  in  the  Journal  of 
American  Chemical  Society  for  December,  1906.  He  concludes 
that  the  use  of  the  ammoniacal  solution  is  useless,  as  plain  ammo- 
niacal water  absorbs  benzene  equally  well,  and  recommends  the 


THE   ANALYSIS    OF   GAS  1 73 

use  of  concentrated  sulphuric  acid  for  absorption  of  benzene 
vapor.  He  states  that  the  absorption  of  ethylene  by  the  sul- 
phuric acid  is  slight  and  may  readily  be  corrected  for;  that  traces 
of  the  higher  defines  may  give  a  slightly  too  high  result  for  the 
benzene,  but  that  this  error  must  be  small,  if  not  inappreciable. 

Dennis  and  McCarthy,  in  the  Journal  of  American  Chemical 
Society,  February,  1908,  declare  that  Morton's  method  does  not 
give  constant  results,  even  when  conditions  are  the  same;  that 
from  mixtures  of  ethylene  and  benzene  it  does  not  quantita- 
tively remove  the  latter,  and  that  it  does  remove  an  indetermi- 
nate amount  of  the  former.  They  also  claim  to  have  located  the 
trouble  with  the  ammoniacal  nickel  nitrate  method.  If  the  latter 
solution  has  taken  up  some  cyanogen  it  is  able  to  quantitatively 
absorb  fairly  large  amounts  of  benzene  vapor;  therefore  if 
cyanogen  compounds  are  present  in  the  gas  to  be  tested,  this 
method  will  give  accurate  results.  They  find  that  ammoniacal 
solutions  of  nickel  cyanide,  prepared  as  they  direct,  will  quanti- 
tatively absorb  benzene  from  ordinary  coal  gas  and  will  not 
absorb  measurable  quantities  of  ethylene  or  of  the  other  con- 
stituents, except  those  absorbable  in  caustic  potash. 

Hydrogen.  Sodium  and  potassium  have  been  experimented 
with  to  a  considerable  extent  to  see  if  their  common  property  of 
absorbing  hydrogen  could  not  be  utilized  in  separating  that  gas 
from  a  mixture  containing  also  methane  and  ethylene.  These 
investigations  have  led  to  the  conclusion  that  neither  potassium 
nor  sodium  is  suitable  for  the  absorption  of  hydrogen  in  ordi- 
nary forms  of  apparatus,  largely  because  of  the  difficulty  of  find- 
ing any  suitable  confining  fluid. 

The  only  absorption  method  for  hydrogen,  then,  which  can  be 
recommended  is  the  one  using  palladium.  This  substance  may 
be  employed  in  either  of  two  forms,  palladium  sponge  or  palla- 
dium black,  the  latter  being  the  more  active.  The  former  is 
prepared  by  heating  the  palladium,  in  portions  of  about  one  gram 
at  a  time,  nearly  to  redness  on  platinum  foil  and  allowing  it  to 
cool  not  too  rapidly.  By  these  means  the  palladium  becomes 
covered  with  a  quantity  of  the  oxide,  which  is  able  to  burn  hydro- 


1/4  GAS  AND   GAS   METERS 

gen  at  ordinary  temperatures  with  evolution  of  heat,  and  this 
heat  raises  the  temperature  of  the  reduced  metallic  palladium  to 
the  point  at  which  it  can  absorb  large  quantities  of  hydrogen  by 
occlusion.  The  palladium  black,  which  is  either  an  oxygen  com- 
pound of  palladium  or  a  mixture  of  metallic  palladium  and  palla- 
dious  oxide,  is  prepared  in  exactly  the  same  manner  as  platinum 
black,  that  is,  palladious  chloride  is  reduced  with  alcohol  in  a 
strongly  alkaline  solution. 

In  view  of  the  simplicity  and  accuracy  of  the  explosion  methods 
for  hydrogen,  carbon  monoxide,  etc.,  the  absorption  of  these 
gases  cannot  be  recommended;  the  only  reagents  needed  for 
explosions  are  pure  hydrogen  and  oxygen  gases.  The  latter 
may  be  bought  in  cylinders  under  pressure,  and  if  each  cylinder 
is  subjected  to  analysis  before  use,  accurate  results  may  be 
secured.  A  cylinder  of  oxygen  costs  $2.75  and  may  be  purchased 
through  any  leading  drug  or  chemical  firm.  The  hydrogen  is 
best  made  in  the  laboratory,  and  a  very  convenient  apparatus 
for  this  purpose  will  be  described  in  connection  with  Hinman's 
analysis  outfit. 

No  convenient  and  accurate  method  is  available  for  the  deter- 
mination of  nitrogen.  It  has  been,  and  still  is,  the  practice  to 
estimate  this  gas  by  difference.  This  is  inaccurate,  it  is  true, 
for  two  reasons:  First,  it  piles  upon  nitrogen  the  errors  accumu- 
lated in  other  determinations;  second,  it  takes  no  account  of 
the  rarer  gases,  such  as  helium,  argon,  neon,  etc.,  which  would 
be  found  with  the  nitrogen.  In  spite  of  these  facts,  the  accuracy 
is  probably  amply  sufficient  for  practical  purposes,  provided  the 
remainder  of  the  analysis  has  been  properly  carried  out. 

In  the  analysis  of  acetylene  an  entirely  different  procedure 
must  be  followed,  because  of  the  activity  of  acetylene  itself  as  a 
chemical  reagent,  and  because  of  its  interference  with  the 
absorption  of  the  gases.  Hempel  recommends  that  the  acety- 
lene be  first  absorbed  by  fuming  sulphuric  acid,  passing  the  gas 
repeatedly  into  the  pipette  until  no  further  diminution  in  volume 
occurs,  and  removing  the  acid  fumes  with  caustic  potash  before 
making  the  final  measurements. 


THE   ANALYSIS    OF   GAS  1 75 

It  is  probable  that  small  amounts  of  acetylene  will  still  remain 
in  the  gas,  as  it  is  extremely  difficult  to  remove  the  last  traces  by 
this  method,  since  the  rapidity  of  absorption  diminishes  with  the 
dilution  of  the  gas;  the  danger  of  dissolving  acetylene  in  the 
absorbents  is  nevertheless  greatly  minimized. 

The  oxygen  is  next  absorbed  with  alkaline  pyrogallol:  Phos- 
phorus must  not  be  used  on  account  of  the  strong  influence 
exerted  by  even  small  amounts  of  acetylene  on  the  absorption 
of  oxygen  by  phosphorus,  thus  rendering  the  results  entirely 
useless.  Hempel  then  directs  the  removal  of  the  last  traces  of 
acetylene  with  ammoniacal  cuprous  chloride  solution;  but  if  this 
be  used,  there  can  be  no  determination  of  carbon  monoxide  by 
this  method.  It  is  therefore  suggested  that  the  last  traces  of 
acetylene  be  removed  by  some  reagent  which  is  indifferent  to 
carbon  monoxide,  and  then  that  the  methane,  hydrogen  and  car- 
bon monoxide  be  determined  by  explosion.  The  method  for 
phosphoretted  hydrogen,  silicon  hydride  and  arseniuretted  hydro- 
gen has  already  been  given. 

Apparatus.  There  are  a  number  of  forms  of  gas  analysis  appara- 
tus on  the  market,  several  of  which  are  excellent;  others  are  meant 
for  rough  work  only,  while  still  others  are  especially  adapted  to  the 
analysis  of  some  peculiar  kind  of  gas.  As  of  interest  to  those 
connected  with  the  illuminating-gas  industry,  four  types  will  be 
considered  briefly,  the  Hempel,  the  Elliott,  the  Orsat-Lunge  and  the 
Hinman.  The  last  named  will  be  discussed  in  detail,  since  it  is  the 
only  one  of  the  four  which  has  not  been  accurately  and  frequently 
described  and  illustrated  in  various  standard  works. 

Hempel's  apparatus  is  the  best  known  of  the  more  accurate 
instruments,  and  in  experienced  hands  gives  excellent  results.  It  is 
seen  in  Fig.  24,  and  consists  of  an  iron  trough,  A,  for  holding  mer- 
cury, a  glass  tube,  D,  graduated  in  millimeters  and  76  to  80  cm.  long; 
a  water  reservoir,  £,  a  leveling  bottle,  H,  a  measuring  bulb,  C,  and 
a  number  of  gas  pipettes  of  the  form,  B,  the  explosion  pipette  differ- 
ing from  these  in  that  it  has  a  glass  stopcock  between  the  two  bulbs, 
and  two  platinum  wires  entering  the  lower  bulb  near  its  top.  In 
measuring  the  sample  of  gas,  the  measuring  bulb,  C,  is  brought  into 


GAS   AND   GAS   METERS 


the  position  shown  in  the  figure  and  pressed  down  tightly  upon  the 
rubber  stopper,  a,  by  means  of  the  clamp,/.  Mercury  is  then  drawn 
out  through  m  until  the  meniscus  of  the  mercury  in  the  measuring 


Fig.  24.    Hempel's  Apparatus  for  Gas  Analysis. 

bulb  is  nearly  tangent  to  the  horizontal  hair  of  a  magnifying  glass, 
which  is  fastened  to  the  apparatus  opposite  /.  The  stopcock  at  m 
is  then  closed,  and  by  turning  a  screw  on  m,  the  mercury  at  /  is 
adjusted  to  exactly  the  correct  height.  By  reading  accurately  the 


THE   ANALYSIS    OF   GAS 


177 


height  of  the  mercury  in  the  manometer,  D,  the  pressure  of  the  gas 
in  the  bulb  is  determined.  After  first  introducing  corrections  for 
variations  in  the  temperature,  the  pressure  of  the  surrounding 
atmosphere  is  ascertained  by  means  of  the  correction  tube  seen  in 


Fig.  24A.    Hempel's  Pipette. 

Fig.  24A.  In  using  this  a  very  small  amount  of  water  is  introduced 
into  A  through  b,  followed  by  mercury  until  the  level  of  the  latter  is 
at  the  zero  mark  of  the  scale  tube,  £,  and  at  a  on  A.  By  sliding  the 
glass  rod,  D,  up  and  down  in  the  adjusting  tube,  c,  the  sharp  adjust- 
ment of  the  height  of  the  mercury  is  made.  The  small  end  of  b  is 
rapidly  sealed  with  a  small  blowpipe  flame;  the  seal  should  occur 
just  above  the  level  of  the  water  in  the  mercury  trough. 

If  now  the  temperature  or  pressure  change  during  the  analysis, 
a  correction  may  easily  be  found  by  replacing  the  correction  tube  in 
the  mercury  trough,  and  again  bringing  the  mercury  to  the  mark  by 
the  use  of  the  adjusting  rod,  c.  The  reading  of  B  will  then  give  the 
volume  to  be  added  to  or  subtracted  from  the  values  found  in  the 
analysis  in  order  to  make  all  the  results  comparable. 

In  using  the  apparatus,  the  capillary  stem  of  a  pipette  is  intro- 
duced into  the  mercury  trough,  and  the  end  of  the  stem  brought 
into  the  measuring  bulb.  The  gas  can  then  be  forced  over  into  the 
pipette,  the  absorption  made,  and  the  gas  returned  to  the  measuring 
bulb.  In  the  case  of  the  absorbent  for  illuminants  it  is  necessary  to 


GAS   AND    GAS   METERS 


completely  fill  the  absorption  pipette  with  the  fuming  sulphuric 
acid,  so  that  the  latter  shall  only  come  in  contact  with  the  mercury 
in  the  capillary.  Taplay  has  made  improvements  on  this  appara- 
tus which  are  in  general  intended  to  simplify  the  manipulation  of 

the  burette  and  pipettes  without  the 
introduction  of  air,  a  difficult  matter 
in  the  ordinary  forms.  This  apparatus 
is  seen  in  Fig.  25,  and  its  manufacture 
and  use  are  described  in  Abady's  "  Gas 
Analysts'  Manual."  The  cost  of  the 
Hempel  apparatus  complete  is  about 

$35- 

The  Elliott  apparatus,  designed  by 
Dr.  A.  H.  Elliott  of  New  York,  is 
intended  for  the  rapid  analysis  of  coal 
or  flue  gases,  and  was  formerly  used  to 
a  considerable  extent.  It  is  not  as 
accurate  as  Hempel 's,  but  is  much 
more  rapid  and  less  delicate,  and, 
therefore,  more  suitable  for  rough 
work.  The  apparatus  in  its  old  and 
improved  forms  is  shown  in  Figs.  26 
and  27.  In  Fig.  26,  A  is  the  laboratory 
tube,  which  holds  about  125  c.c. ;  B 
is  the  measuring  tube  with  a  capacity 
of  100  c.c.  from,  the  zero  mark  to  the 

scratch,  c,  on  the  capillary  tube;  the  graduations  are  tenths  of  a 
cubic  centimeter.  /  is  a  three-way  cock  opening  into  A,  to  the 
leveling  bottle  and  through  its  stem.  A  and  B  are  connected  by 
capillary  glass  tubes,  a  tight  joint  being  made  by  means  of  pressure 
tubing.  M  is  a  funnel  of  about  60  c.c.  capacity,  and  between  it 
and  A  is  a  glass  stopcock,  F,  the  end  of  the  latter  being  ground  to 
fit  tightly  into  the  end  of  M.  In  using  this  apparatus  the  air  is  first 
expelled  by  water,  the  gas  sample  is  admitted  through  F,  the  water 
being  drawn  off  through  7.  The  gas  is  then  measured  in  B,  100 
c.c.  being  taken.  The  reagents  are  introduced  into  At  and  the 


Fig.  246.  Hempel's  Correction 
Tube. 


THE   ANALYSIS    OF   GAS 


179 


absorptions  made  in  that  tube,  the  gas  being  returned  to  B  for 
measurement,  after  each  absorption.  After  the  use  of  each  reagent, 
A  must  be  washed  out  with  water.  The  explosions  are  made  in 
a  special  burette.  This  apparatus  complete  costs  in  the  neighbor- 
hood of  $25. 


Fig.  25.     Taplay's  Modification  of  Hempel's  Apparatus. 

The  Orsat-Lunge  is  a  most  convenient  form  of  apparatus  for  the 
rapid  and  partial  analysis  of  gas.  It  is  put  up  in  a  wooden  box, 
with  removable  front  and  back,  and  having  a  handle  on  the  top; 
thus  it  may  readily  be  transported  and  the  analysis  made  on  the 
spot.  It  consists  of  a  measuring  tube,  A,  Fig.  28,  of  100  c.c.  capac- 


i8o 


GAS   AND   GAS   METERS 


ity,  which  is  surrounded  by  a  water  jacket  for  the  purpose  of  keeping 
the  temperature  constant.  At  its  base  this  tube  is  connected  with 
the  leveling  bottle,  B,  which  is  filled  with  water,  brine  or  mercury. 
At  its  top  the  measuring  tube  is  joined  by  means  of  capillary  tubing 
of  small  bore  with  three  absorption  vessels,  C,  D,  and  E,  which  may 
be  connected  with  or  shut  off  from  the  measuring  tube  by  means  of 

glass  stopcocks.  The  outlet  of 
each  of  these  vessels  is  connected 
with  a  similar  vessel  in  the  rear 
furnished  with  a  tubulated  exit, 
which  in  turn  is  attached  to  a 
rubber  bag,  whereby  air  is  excluded 
and  the  reagent  may  be  driven 
back,  if  necessary. 

The  first  vessel  contains  caus- 
tic potash,  the  second,  alkaline 
pyrogallol,  and  the  third,  acid 
cuprous  chloride  solution.  In 
order  to  increase  the  surface  ex- 
posed to  the  gas,  each  tube  is 
filled  with  narrow  glass  tubes  set 
vertically;  while  in  addition  to 
these  the  cuprous  chloride  vessel 
contains  pieces  of  copper  wire 
which  keep  the  solution  reduced. 
In  some  forms  of  this  appara- 
tus there  is  a  fourth  vessel  containing  palladium  sponge  for  the 
absorption  of  the  hydrogen. 

The  ga's  is  measured  and  forced  over  into  the  vessel,  C,  for 
absorption  of  carbonic  acid;  back  to  the  burette  for  measurement; 
then  into  D  and  back  to  the  burette;  then  into  D,  from  here  into 
C  for  the  removal  of  acid  vapors,  and  thence  to  the  burette.  The 
entire  analysis  may  be  performed  with  great  rapidity,  and,  espe- 
cially if  mercury  be  the  confining  fluid,  with  considerable  accu- 
racy. It  does  not  admit  of  the  determination  of  methane,  illumi- 
nants  and  nitrogen,  but  it  does  furnish  information  of  great  value 


Fig.  26. 


Elliott's  Analysis  Outfit, 
Old  Style. 


THE  ANALYSIS   OF   GAS 


181 


Fig.  27.     Elliott's  Analysis  Outfit,  New  Style. 


Fig.  28.     Orsat-Lunge  Analysis  Apparatus. 


1 82  GAS   AND   GAS   METERS 

to  a  gas  maker,  and  especially  to  the  manager  of  a  water  gas  set. 
The  outfit  costs,  with  three  pipettes,  but  $20. 

Hinman's  apparatus  is  the  least  known  of  the  four,  and  yet  is 
probably  the  most  accurate.  So  far  as  the  writer  knows,  but  one 
printed  description  has  ever  been  given  of  it,  and  as  this  is  to-day 
rarely  available,  it  seems  desirable  to  insert  it  at  this  point. 
Major  Hinman  says:  "An  apparatus  was  desired  which  should 
be  as  far  as  possible  free  from  fragile  or  costly  parts,  and  which 
without  being  too  complicated  should  require  no  corrections  to 
be  made  for  variations  in  the  pressure,  temperature  or  aqueous 
vapor;  reliable  results  rather  than  minute  accuracy  being  desired." 

"The  apparatus  finally  adopted  operates  on  the  same  principles 
as  Williamson  and  Russell's,  except  that  in  my  apparatus  the 
gas  is  not  exploded  in  the  measuring  tube  but  in  a  bulb  for  that 
special  purpose.  The  trough  is  nearly  the  same  as  that  of  Devere, 
and  pipettes  are  also  used." 

"The  apparatus  as  made  consists  of  a  measuring  tube,  a, 
Fig.  29,  about  230  mm.  long  and  about  20  mm.  in  diameter, 
divided  into  one-fortieth  of  an  inch  and  calibrated  with  mercury 
as  described  by  Bunsen.  The  tube  is  firmly  held  by  a  clamp  on 
the  end  of  the  rod,  &,  which  rod  slides  up  and  down  c  and  is 
clamped  in  any  position  by  the  screw,  d.  A  slow  motion  is  given 
to  c  and  thus  to  the  measuring  tube  by  means  of  the  milled- 
headed  nut,  e,  which  works  along  a  thread  cut  on  the  rod,  /, 
which  is  firmly  secured  to  the  body  of  the  apparatus.  The  screw, 
g,  can  be  turned  in  so  that  its  end  just  fits  into  a  longitudinal 
slot  in  the  rod,  /.  By  this  means  c  is  prevented  from  turning 
around  /,  and  the  measuring  tube  can  thus  be  kept  exactly  over 
its  well;  or  g  can  be  used  to  clamp  c  in  any  position. 

"  The  pressure  tube,  h,  is  about  200  mm.  long,  and  has  a  diameter 
of  only  6  mm.  A  mass  of  lead  covered  with  sealing  wax  is 
attached  to  the  lower  part  of  h,  so  that  when  it  is  filled  with  air, 
it  will  keep  upright  when  it  is  suspended  from  an  eye  at  the  top. 
The  pressure  tube  is  hung  by  a  wire  from  the  end  of  the  arm,  i, 
which  slides  with  friction  along  the  rod,  /. 

"  The  mercurial  trough  is  of  cast  iron,  and  consists  of  the  plate,  I, 


THE   ANALYSIS    OF   GAS  183 

which  is  about  130  mm.  square,  15  mm.  thick,  and  has  a  groove 
in  its  upper  surface  10  mm.  wide,  6  mm.  deep  and  5  mm.  from 
the  edge;  the  well,  k,  which  is  about  240  mm.  deep  and  30  mm. 
in  inside  diameter;  and  the  side  well,  m,  for  the  pipette,  which  is 
of  the  same  depth  as  k,  but  part  of  it  extends  40  mm.  above  the 


erf; 


Fig.  29.     Hinman's  Analysis  Apparatus. 

top  of  /;  m  is  10  mm.  wide  and  90  mm.  broad.  The  wells,  m 
and  k,  have  walls  6  mm.  thick.  Of  course  k,  I  and  m  are  all  cast 
in  one  piece. 

"  The  groove  in  /  has  cemented  into  it,  by  means  of  a  cement 
composed  of  beeswax  and  rosin,  a  rectangular  trough  of  plate 
glass  5  mm.  thick,  cemented  with  the  same  cement  into  a  sheet- 
iron  frame,  j,  which  is  made  by  bending  a  sheet  of  the  right  size 


1 84  GAS   AND   GAS   METERS 

into  a  box  without  ends,  and  then  cutting  out  the  sides  so  as  to 
leave  only  a  strip  12  mm.  wide  on  each  edge.  The  legs,  n,  are 
secured  onto  the  plate,  /. 

"  The  pipettes  consist  of  a  bulb,  o,  of  a  little  larger  capacity  than 
the  measuring  tube,  open  at  one  end  and  at  the  other  melted  to  a 
tube  about  5  mm.  in  diameter,  having  a  bore  of  i  mm.,  bent  so 
that  when  it  is  put  into  the  side  well,  m,  the  point  of  the  pipette 
can  be  brought  directly  under  the  measuring  tube.  The  other 
end  of  the  bulb  is  joined  to  the  end  of  a  piece  of  good  rubber 
tubing,  about  300  mm.  long,  with  rather  thick  walls  and  small 
bore,  and  the  other  end  of  which  is  connected  with  a  small  syphon 
which  dips  to  the  bottom  of  a  strong  glass  bottle,  p,  of  rather 
larger  capacity  than  the  bulb,  o.  Immediately  below  the  bulb  is 
a  screw  clip,  q. 

"  The  pipette  is  held  in  a  stand  devised  by  my  assistant,  Mr. 
Lewis.  It  consists  of  two  discs  of  wood,  rr  (Fig.  29)  (cut  away  so 
as  to  fit  the  bulb),  to  which  are  screwed  three  rods  of  iron,  ss,  so 
as  to  hold  the  bulb  between  the  discs  and  at  the  same  time  form  a 
tripod  to  support  the  pipette.  The  pipette  tube  is  supported  by 
being  attached  to  a  semi-cylindrical  piece  of  metal,  /,  which  is 
fastened  into  the  upper  disc,  r.  This  style  of  pipette  is  to  hold 
reagents  for  absorption. 

"  I  have  invented  another  sort  of  pipette  in  which  to  explode 
gases.  The  bulb  is  of  the  same  capacity  as  the  former  one,  but 
the  sides  are  12-15  mm-  thick,  and  instead  of  the  pipette  tube 
being  melted  onto  the  bulb,  it  is  ground  into  the  top  with  emery 
and  then  cemented  in  with  shellac  containing  a  little  Venice  tur- 
pentine. Two  grooves  are  made  in  opposite  sides  of  the  end  of 
the  pipette  tube,  where  it  is  ground  into  the  bulb,  in  which  are 
platinum  wires,  the  ends  of  which  approach  within  i  mm.  of 
each  other.  Care  is  taken  to  have  the  form  of  the  pipette  such  that 
all  the  gas  will  be  expelled  from  the  bulb  when  the  mercury  rises. 

"  The  apparatus  is  used  in  the  following  manner:  Clean  mercury 
is  poured  into  the  well  until  it  is  about  8  mm.  deep  above  the  top  of 
/.  A  drop  of  water  is  put  in  the  end  of  the  pressure  tube,  which  is 
suspended  so  that  the  bottom  nearly  touches  /,  and  water  of  the 


THE   ANALYSIS    OF   GAS  185 

temperature  of  the  room  is  poured  in  until  the  glass  vessel  is  nearly 
full.  Air  is  then  taken  out  of  or  added  to  the  pressure  tube  until 
the  mercury  in  the  lower  part  of  the  tube  is  just  on  a  level  with  the 
top  of  a  straight-edged  piece  of  glass,  v,  which  is  fixed  just  behind 
the  pressure  tube  and  measuring  tube,  so  that  its  top  edge  is  parallel 
to  and  about  15  mm.  above  the  top  of  /. 

"  The  measuring  tube  being  thoroughly  cleaned,  and  a  drop  of 
water  spread  over  the  sides,  is  fixed  in  the  clamp,  a  thin  slice  of  cork 
being  placed  between  each  side  of  the  clamp  and  the  tube.  The 
tube  is  then  placed  upright  in  a  small,  long-handled  cup  of  mercury, 
like  that  used  by  Doyere,  and  is  lowered  through  the  water  into  the 
mercury  well.  The  piece,  c,  is  then  put  over  b  and  fixed  into  posi- 
tion on  the  rod,/. 

"A  clean  pipette,  full  of  mercury,  is  then  lowered  into  the  trough, 
and  the  point  brought  directly  under  the  measuring  tube,  which  is 
then  lowered,  so  that  the  pipette  touches  the  top  of  the  measuring 
tube.  The  bottle  is  placed  on  the  table,  the  screw  clip,  q,  loosened, 
and  the  air  is  forced  over  into  the  bulb,  0,  of  the  pipette. 

"When  the  pipette  tube  has  become  filled  with  mercury,  the  meas- 
uring tube  is  raised,  and  the  pipette  withdrawn.  The  air  in  the 
pipette  is  then  displaced  by  mercury,  and  if  the  gas  to  be  analyzed 
can  be  taken  from  a  rubber  tube,  the  end  of  this  is  slipped  over  the 
pipette  tube,  and  the  gas  then  drawn  in. 

"The  pipetteis  put  into  the  well, placed  under  the  measuring  tube, 
which  is  lowered  a,  little,  and  the  gas  forced  into  it  by  raising  the 
bottle,  pj  to  the  position,  /,  and  opening  the  clip,  q.  If  desirable, 
the  gas  can  be  bubbled  directly  into  the  measuring  tube  by  means  of 
a  properly  bent  tube. 

"  When  as  much  gas  as  is  desired  is  in  the  measuring  tube,  the 
pipette  or  other  tube  is  withdrawn,  the  measuring  tube  raised  or 
lowered  until  the  top  of  the  mercury  in  it  is  on  a  level  with  the  top  of 
the  glass,  v,  and  if  the  mercury  in  h  is  not  at  the  same  height,  it  is 
adjusted  by  altering  the  height  of  the  mercury  in  the  trough,  or  by 
adding  hot  or  cold  water  to  that  surrounding  the  tubes,  care  being 
taken  to  thoroughly  mix  the  water  by  agitation  with  a  stirrer.  The 
gases  in  the  measuring  and  pressure  tubes  are  thus  kept  at  the  same 


1 86  GAS   AND   GAS   METERS 

pressure  and  temperature,  and  are  saturated  with  moisture.  The 
reading  of  the  measuring  tube  is  effected  by  a  telescope  fixed  at 
some  distance  from  the  apparatus.  As  the  mercury  is  always  at  the 
same  height,  the  telescope  is  always  in  the  same  position. 

"  When  it  is  desired  to  subject  the  gas  to  the  action  of  any  reagent, 
a  pipette  containing  a  few  drops  of  the  reagent  (the  rest  of  the 
pipette  being  filled  with  mercury)  is  introduced  into  the  trough, 
and  the  gas  drawn  over  as  before  described,  and  is  then  shaken  up 
with  the  reagent. ' 

"  When  the  gas  is  to  be  transferred  back  to  the  measuring  tube, 
mercury  is  drawn  through  the  tube  to  remove  any  traces  of  the 
reagent,  as  it  is  essential  that  none  of  the  reagent  should  be  trans- 
ferred with  the  gas.  The  point  of  the  pipette  being  under  the 
measuring  tube,  the  bottle,  p,  is  raised,  the  clip,  q,  opened,  and  the 
gas  is  forced  into  the  measuring  tube.  When  the  gas  is  nearly  over, 
the  clip,  q,  is  nearly  closed,  so  that  the  gas  passes  quite  slowly;  the 
pipette  is  raised  by  a  block  of  wood  under  its  base,  so  that  its  point 
is  40  to  50  mm.  above  the  surface  of  the  mercury  in  the  measuring 
tube.  The  progress  of  the  liquid  in  the  pipette  tube  must  be 
watched  carefully,  and  when  it  is  about  20  mm.  from  the  end,  the 
clip,  q,  is  closed,  and  by  carefully  pinching  the  rubber  tube  above 
the  clip,  the  liquid  is  forced  within  i  or  2  mm.  of  the  point  of  the 
pipette  tube ;  the  point  of  the  pipette  is  then  brought  under  the  sur- 
face of  the  mercury  by  raising  the  measuring  tube,  and  the  pipette 
withdrawn.  The  quantity  of  gas  left  in  the  pipette  tube  would  be 
quite  unmeasurable  if  it  were  five  times  larger." 

One  or  two  changes  have  been  made  in  the  apparatus  since  this 
description  was  written,  which  make  for  greater  accuracy  and  ease 
of  manipulation.  The  pressure  tube  rests  with  its  open  end  in  a 
groove,  while  the  upper  end  fits  into  a  cup-shaped  depression  in  a 
flexible  steel  spring,  whose  ends  are  held  under  projections  on 
either  side  of  the  top  of  the  framework  which  holds  the  glass  sides. 
This  eliminates  the  necessity  of  the  mass  of  lead,  the  arm,  i,  and 
the  wire  used  for  suspension.  The  narrow  neck  of  the  pressure 
tube  bears  three  scratches  corresponding  in  height  to  three  similar 
marks  on  the  glass  window  in  the  rear;  the  mercury  in  the  tube  is 


THE   ANALYSIS    OF   GAS  l8/ 

set  level  with  two  of  these  marks  at  the  start,  and  brought  to  the 
same  position  before  each  measurement. 

The  writer  has  also  made  a  slight  change  in  the  pipette  which  has 
proved  very  satisfactory.  The  screws  holding  the  legs  to  the  top 
plate  are  removed,  and  a  circular  strip  of  brass  with  the  ends 
soldered  together,  is  placed  around  the  plate.  This  strip  is  punc- 
tured by  three  holes  through  which  the  screws  pass  and  fasten  it 
securely  to  the  top.  The  brass  projects  about  i  J  inches  above  the 
top  surface,  thus  making  a  shallow  cup  in  which  the  bottle,  p,  rests. 
It  is  often  necessary  in  the  course  of  an  analysis  to  place  the  bottle 
on  top  of  the  pipette,  and  then  change  the  position  of  the  latter. 
The  brass  ring  prevents  the  bottle  from  sliding  off  or  tipping  over, 
a  thing  very  liable  to  happen;  it  thus  enables  the  operator  to  move 
the  pipette  more  quickly  and  with  less  need  of  care. 

The  trough,  k,  is  tapped  about  one-half  way  down  and  a  steel 
tube  bearing  a  three-way  cock  inserted,  the  other  end  of  this  tube 
connected  with  a  rubber  bulb  whose  upper  end  is  joined  to  a  glass 
tube  if  inches  in  diameter  and  open  at  the  top;  the  opening,  how- 
ever, is  only  five-sixteenths  of  an  inch  in  diameter.  This  tube 
is  held  vertically  against  the  side  of  the  trough  by  wire.  By  means 
of  the  three-way  cock,  mercury  may  be  drawn  off  from  the  trough 
into  a  bottle;  or,  by  opening  the  cock  and  squeezing  the  bulb,  it 
may  be  forced  into  the  vertical  glass  tube  or  allowed  to  flow  from 
the  latter  into  the  trough.  This  enables  rapid  adjustment  of  the 
height  of  mercury  in  the  trough,  and  consequently  rapid  and 
accurate  alignment  of  the  mercury  in  the  pressure  tube. 

A  hydrogen  generator  has  been  devised  which  works  admirably 
and  is  seen  in  Fig.  29.  The  acid  is  introduced  into  the  bulb,  a', 
and  is  raised  or  lowered  by  mercury  from  the  bottle.  The  zinc  is 
in  bulb,  &',  and  is  held  in  place  by  a  glass  rod  flattened  at  the  end 
and  passing  through  the  rubber  stopper,  c',  which  is  wired  securely 
on.  In  the  bulb,  d1 ',  is  placed  a  little  caustic  potash  solution,  for 
the  purpose  of  catching  any  acid  fumes.  The  end,  e',  may  be 
connected  to  a  specially  bent  tube  which  is  readily  inserted  under 
the  measuring  tube  or  eudiometer,  and  thus  the  hydrogen  passes 
directly  into  the  latter. 


1 88  GAS   AND   GAS   METERS 

The  apparatus  is  mounted  on  a  table  39  inches  by  27  inches, 
covered  with  oilcloth  and  having  a  small  hole  in  one  corner  by 
which  any  mercury  which  has  been  spilled  on  the  table  may  be 
drawn  off.  Twenty  inches  from  the  floor  is  a  shelf  which  serves 
to  hold  the  stirrer,  caustic  potash,  and  sulphuric  acid  bottles, 
waste  mercury  bottle,  the  cup  used  in  lowering  the  eudiometer 
and  pressure  tube  into  place,  niters,  etc.  These  niters  are  used 
for  drying  the  eudiometer;  the  most  convenient  method  is  to  fold 
two  of  them  double  and  insert  in  the  cleft  end  of  a  stick.  By 
rolling  the  filter  around  the  stick  a  most  effective  drier  is 
secured. 

From  one  corner  of  the  shelf  projects  a  small  board  pierced  by 
a  2-inch  hole,  in  which  is  placed  the  neck  of  a  liter  bottle  used  for 
purifying  the  mercury.  The  mouth  of  the  bottle  is  closed  by  a 
rubber  stopper  bearing  an  iron  tube  and  stopcock,  while  there  is 
a  hole  in  the  bottom  of  the  bottle  directly  opposite  the  neck,  through 
which  the  impure  mercury  and  the  sulphuric  acid  are  poured  in. 

The  pipettes  and  hydrogen  generator,  when  not  in  use,  are  kept 
in  a  glass  case,  the  bottles  being  left  on  top  of  the  pipettes  so  that 
the  pressure  is  always  outward. 

For  the  explosion,  the  writer  uses  a  Wimshurst  machine,  which 
sets  on  an  adjoining  bench,  and  from  which  wires  pass  to  the 
analysis  table.  This  has  proved  most  satisfactory;  the  machine 
occupies  but  little  room,  and  by  means  of  the  wires  the  spark  can 
be  passed  while  the  explosion  pipette  is  still  in  position  under  the 
eudiometer.  The  entire  apparatus  costs  $300.  The  Wimshurst 
machine  and  mercury  are  extra;  the  former  costs  $12,  while  about 
75  pounds  of  the  latter  are  required. 

A  few  of  the  minor  precautions  to  be  observed  in  the  use  of  this 
apparatus  may  be  of  service  to  those  using  it  for  the  first  time. 
The  eudiometer  should  be  moistened  with  a  very  small  amount  of 
water  before  being  filled  with  mercury,  and  the  pressure  tube 
should  likewise  receive  a  small  drop  of  water  only;  if  more  is  used 
it  will  obscure  the  reading  of  the  mercury  meniscus. 

All  pipettes  should  be  tested  for  a  leak  by  placing  the  moistened 
finger  tip  over  the  end  of  the  capillary,  and  observing  whether  the 


THE  ANALYSIS   OF   GAS  189 

mercury  in  the  latter  recedes  continuously  when  the  bottle  is 
lowered. 

Wash  out  the  Nordhausen  acid  as  soon  as  the  absorption  is 
complete  and  the  sample  returned  to  the  eudiometer;  use  ordinary 
sulphuric  acid  for  the  first  washings,  diluting  it  towards  the  end. 
The  mercury  must  then  be  drawn  off  and  the  pipette  dried  by 
aspirating. 

It  is  well  to  leave  the  pipettes  under  the  eudiometer  while  the 
absorptions  are  going  on,  since  in  this  case  if  any  pressure  or 
vacuum  is  created  there  will  be  no  loss  of  the  sample.  In  removing 
a  pipette  from  under  the  eudiometer  the  latter  should  be  lowered  a 
trifle  to  prevent  water  from  being  sucked  in. 

When  adding  oxygen  for  the  explosion,  draw  over  at  first  only 
one-half  of  the  total  quantity  of  oxygen  to  be  used,  and  explode; 
then  draw  over  the  rest  and  explode  again;  this  will  prevent 
burning  the  nitrogen. 

For  purification  of  the  mercury,  the  author  uses  strong  sulphuric 
acid  and  mercurous  sulphate,  allowing  the  mercury  to  stand  under 
the  reagents  until  needed,  when  it  is  drawn  off  by  the  cock  at  the 
bottom  of  the  purification  bottle.  The  oxygen  used  should  always 
be  analyzed;  this  is  easily  and  accurately  done  by  the  explosion 
with  hydrogen. 

The  advantages  and  disadvantages  of  this  form  of  apparatus 
as  compared  with  others  may  now  be  briefly  considered.  Major 
Hinman  made  a  number  of  experiments  to  compare  it  with  the 
Hempel  under  varying  conditions.  The  results  showed  that  while 
Hempel's  was  equally  reliable  for  absorptions,  the  determinations 
of  hydrogen  and  nitrogen  were  far  more  accurate  with  the  Hinman. 
The  latter  is  very  costly;  parts  of  it,  notably  the  pipette  stems,  are 
fragile  and  easily  broken,  and  it  is  distinctly  not  intended  for  rapid 
work. 

On  the  other  hand,  it  gives  very  accurate  results;  the  carbon 
monoxide  is  determined  by  explosion,  eliminating  the  errors 
attendant  upon  the  use  of  cuprous  chloride;  there  is  no  need  of 
corrections  for  temperature,  pressure  or  tension  of  aqueous  vapor; 
the  absorptions  are  complete  in  a  short  time;  mercury  is  the  con- 


19° 


GAS   AND   GAS   METERS 


fining  fluid,  so  there  is  no  chance  for  loss  due  to  the  solubility  of 
certain  constituents  of  the  gas  in  water;  there  are  no  glass  stop- 
cocks to  become  stuck  or  to  leak;  the  explosions  are  made  without 
danger  of  burning  the  nitrogen,  while  the  readings  may  be  made 
with  extreme  accuracy. 

On  the  whole  this  apparatus  seems  to  be  the  most  satisfactory 
where  absolutely  trustworthy  results  are  desired;  it  will  of  course 
never  be  employed  for  rapid  approximate  work,  and  should  never 
be  placed  in  the  hands  of  any  but  a  skilful  and  competent  manipu- 
lator. 

The  calculations  involved  in  the  use  of  Hinman's  apparatus  may 
best  be  explained  by  two  concrete  instances. 


Divisions.* 

Vol.  in  c.c. 

J47-3 

22.  90 

Gas  taken. 

146.7 

22.82 

Vol.  after  absorption  of  carbonic  acid. 

146.5 

22.79 

Vol.  after  absorption  of  oxygen. 

138.2 

21.58 

Vol.  after  absorption  of  illuminants. 

326.4 

48.91 

Vol.  after  adding  oxygen. 

84.9 

13.72 

Vol.  after  explosion  with  oxygen 

8.8 

2.49 

Vol.  after  absorbing  carbonic  acid  from 

explosion. 

64.0 

10.65 

Vol.  after  adding  hydrogen. 

23.0 

4-59 

Vol.  after  explosion  with  hydrogen. 

*  American  Journal  of  Science  and  Arts,  September,   1874. 


Vols.  in  c.c. 

Vol. 
in  c.c. 

Per 

cent. 

o.47N2 

(A)  CH4+CO+H2=2i.n 

22.  90 

100.  00 

Gas 
taken. 

6.  06  H2O  formed         ) 
2.02  O2  left                  J 

(B)  CH4+CO=n.23 

.08 

•°3 

•35 
•13 

C02 

02 

27-33  O2  added           ) 
25.31  O2  used              j 

(C)  2CH4+iCO  +  iH2=25.3i 

I.  21 

5-29 

hydro- 
car- 
bons 

11.23  CO2  formed       ) 
21.  ii  combustible  gas  ) 

2(C)-(A)=3CH4=29.5i 

9.84 

i-39 

42.97 
6.06 

CH4 
CO 

(A)-(B)=Ha      =9-88 

9.88 

43-15 

H2 

(B)-CH4=CO    =1.39 

•47 

2.05 

N 

THE   ANALYSIS   OF   GAS 


191 


Divisions. 

Vol.  in  c.c. 

149.  7 

23.26 

Gas  taken. 

149.2 

23.19 

Vol.  after  absorption  of  carbonic  acid. 

149.0 

23.16 

Vol.  after  absorption  of  oxygen. 

140.3 

21.88 

Vol.  after  absorption  of  illuminants. 

328.0 

49.14 

Vol.  after  adding  oxygen. 

82.8 

5-9 

I3-4I 
2.06 

Vol.  after  explosion  with  oxygen. 
Vol.    after   absorbing   carbonic   acid   from 

explosion. 

45-3 

7.88 

Vol.  after  adding  hydrogen. 

14.2 

3.28 

Vol.  after  explosion  with  hydrogen. 

Vols.  in  c.c. 

Vol. 
in  c.c. 

Per 
cent. 

o.  53  nitrogen 

(A)  CH4+CO  +  H=2i.35 

23.26 

100.  00 

Gas  taken. 

4.  60  H2O  formed 

(B)CH4+CO=n.35 

.07 

•3° 

C02 

1.53  02left 

(C)2CH4+iCO+JH=25.73 

•3 

•13 

02 

27.26  O2  added 

2(C)-(A)=3CH4=3o.ii 

1.28 

5-5° 

hydro- 

carbons 

25.73  o2  used 

(A)-(B)=H=io.oo 

10.04 

43.16 

CH4 

u.  35  CO2  formed 

(B)-CH4=CO=  1.31 

I-3I 

5.63 

CO 

21.  35  combustible 

10.00 

42.99 

H2 

gas 

•53 

2.28 

N 

As  has  already  been  said,  no  other  forms  of  apparatus  will  be 
described  here,  but  if  the  reader  is  interested  in  some  of  those 
more  recently  proposed,  he  should  consult  the  Journal  of  American 
Chemical  Society  Abstracts  forDecember  5, 1907,  and  March  5, 1907 ; 
the  Journal  of  Gas  Lighting,  January  21,  1908,  and  September  17, 
1907;  and  the  Progressive  Age  for  December  2,  1907,  etc.  In 
order  that  some  idea  may  be  given  of  the  results  of  gas  analysis, 
two  or  three  tables  are  inserted  in  the  appendix  giving  data  taken 
from  various  sources,  but,  with  the  exception  of  the  natural  gas 
figures,  principally  from  the  reports  of  the  Massachusetts  State 
Gas  Inspectors. 

If  properly  interpreted,  there  is  nothing  which  will  give  a 
manager  so  much  information  as  to  the  running  of  his  plant  as  an 
accurate  chemical  analysis.  From  it  he  can  readily  calculate  the 
heating  value  of  the  gas,  in  the  manner  which  will  be  shown  in  the 


GAS   AND   GAS   METERS 

discussion  of  calorimetry ;  he  can  determine  whether  air  is  being 
admitted ;  whether  heats  are  too  high  or  too  low ;  whether  a  greater 
yield  may  safely  be  secured,  and  many  other  factors  of  prime 
importance.  The  writer  is  indebted  to  Mr.  C.  D.  Jenkins,  State 
Gas  Inspector  of  Massachusetts,  one  of  the  most  experienced  and 
competent  gas  analysts  in  the  United  States,  for  the  following  clear 
and  concise  statements  on  the  interpretation  of  gas  analyses. 

"Coal  Gas.  The  diluents  should  not  exceed  5  per  cent  in  the 
purified  gas.  High  nitrogen,  especially  with  much  carbonic  acid, 
would  indicate  that  furnace  gases  had  been  drawn  in  through  a 
leaky  retort.  High  nitrogen  with  oxygen  would  indicate  air  leaks. 
Both  of  these  conditions  depend  on  the  exhauster  carrying  a  vacuum 
on  the  generating  plant.  High  carbonic  acid  with  normal  nitrogen 
(and  no  oxygen)  would  point  to  the  use  of  a  wet  coal  or  to  a  large 
per  cent  of  oxygen  in  the  coal.  The  three  diluents  affect  the 
candlepower  directly,  as  well  as  volumetrically;  their  action  on  the 
heating  value,  however,  is  simply  to  reduce  the  latter  by  the  volume 
of  the  inert  gases  introduced.  The  amount  of  illuminants  does 
not  of  itself  furnish  a  criterion  of  the  candlepower  of  the  gas,  but 
must  be  considered  in  conjunction  with  the  amount  of  the  other 
gases.  An  average  per  cent  of  illuminants,  high  methane,  low 
hydrogen  and  average  carbon  monoxide,  should  indicate  a  good 
candlepower  gas  with  high  heating  value;  while  with  the  same 
amount  of  illuminants,  low  methane,  high  hydrogen  and  average 
to  high  carbon  monoxide,  the  candlepower  and  heating  value  both 
suffer,  but  the  latter  in  not  as  great  proportion  as  the  former. 

"  The  methane  is  a  valuable  constituent  from  the  standpoint  of 
both  heating  and  lighting  power.  It  is  an  indicator  of  heats  and 
yields,  high  heats  and  large  yields  giving  a  low  methane  content, 
with  an  excess  of  hydrogen. 

"  Water  Gas.  The  diluents  are  liable  to  vary  more  than  is  the 
case  with  coal  gas,  on  account  of  the  carbonic  acid  which  may  be 
allowed  to  remain  in  the  gas.  A  large  amount  of  carbonic  acid 
would  indicate  too  long  a  run,  too  low  a  heat  in  the  generator  or 
too  thin  a  fire. 

"  Nitrogen  would  come  from  gases  left  in  the  apparatus  during 


THE   ANALYSIS   OF   GAS  193 

the  'blow/  and  should  therefore  be  low.  The  illuminants  are 
more  nearly  uniform  than  in  coal  gas,  and  their  proportion  will  give 
a  better  idea  of  the  candlepower.  The  illuminants  and  methane 
coming  from  the  oil  gas,  made  in  carburetting  the  blue  water  gas, 
should  be  in  the  same  relation  as  in  oil  gas;  a  large  proportion  of 
methane  would  indicate  a  breaking  down  of  the  illuminants  with 
consequent  loss  of  candlepower. 

"In  mixed  coal  and  water  gas  the  amount  of  carbon  monoxide 
would  indicate  the  relative  proportion  of  each  gas;  by  assuming  a 
normal  analysis  for  one,  the  other  can  be  calculated." 


PART  III. 


CALORIMETRY,    SPECIFIC    GRAVITY    AND 
PRESSURE. 


PART  III. 

CALORIMETRY,     SPECIFIC     GRAVITY    AND 
PRESSURE. 


CHAPTER  I. 
THE  JUNKER  AND  BOYS  CALORIMETERS. 

THE  subject  of  calorimetry  is  every  year  becoming  of  greater 
interest  and  importance,  and  is  destined,  in  the  very  near  future, 
to  occupy  the  foremost  position  among  methods  of  gas  testing. 
Indeed,  it  seems  essential  and  just  that  this  should  be  so,  if  the 
history  of  the  modern  gas  industry  be  considered.  It  is  coming 
to  be  accepted  as  a  fact  that,  as  a  general  rule,  from  75  to  90  per 
cent  of  the  gas  burned  is  consumed  in  Welsbach  burners  and  in 
stoves  or  other  heating  appliances.  Now  if  this  be  true,  the  heat- 
ing value  of  the  gas  is  clearly  the  factor  to  be  reckoned  with,  and 
it  is  predicted  that  before  long,  governmental  regulations  will 
require  a  certain  heating  value,  rather  than  a  candlepower  limit, 
as  a  standard  for  gas.  Indeed,  to  continue  the  candlepower 
standard  is  simply  to  place  a  premium  on  inefficiency  and  to  pro- 
tect the  few  at  the  expense  of  the  many;  for  a  high  candlepower 
per  se  benefits  only  those  who  use  flat-flame  burners,  and  may 
prove  a  real  injury  to  the  consumers  who  use  Welsbachs. 
Already  candlepower  tests  have  been  abandoned  in  Wisconsin, 
and  the  Public  Service  Commission  of  the  Second  District  of 
New  York  State  is  conducting  extensive  researches  tending  in 
this  direction.  There  is  no  doubt  that  photometric  work  will 
persist  in  many  localities  and  for  varied  reasons  for  a  long  time 
to  come;  but  the  writer  is  firmly  of  the  opinion  that  the  calori- 
metric  test  should  be  brought  more  and  more  to  the  fore,  and 

197 


198  GAS   AND   GAS   METERS 

should  wherever  possible  be  substituted  for  candlepower  require- 
ments. 

The  calorimetry  of  gas  is  the  science  of  determining  the  num- 
ber of  heat  units  given  off  by  .the  perfect  combustion  of  a  unit 
volume  of  the  gas  under  standard  conditions.  Before  pro- 
ceeding further,  it  may  be  well  to  insert  a  few  definitions  which 
will  assist  in  the  comprehension  of  what  follows.  A  British 
Thermal  Unit,  or  a  B.T.U.,  as  it  is  commonly  abbreviated,  is  the 
amount  of  heat  required  to  raise  the  temperature  of  one  pound 
of  water  at  its  maximum' density  (i.e.,  39.1°  F.)  through  i°  F. 
A  large  Calorie  or  Kg.-calorie  is  the  quantity  of  heat  necessary 
to  raise  the  temperature  of  i  Kg.  of  water  at  its  maximum  den- 
sity, i°  C.  A  small  calorie  or  g.-calorie  is  the  same  as  the  above, 
save  that  the  amount  of  water  to  be  heated  is  i  g.1 

In  France  and  some  other  countries  the  heating  value  of  a  gas 
is  expressed  in  Calories  per  cubic  meter;  this  means  the  number 
of  Kgs.  of  water  which  can  be  raised  in  temperature  from  o°  to 
i°  C.  by  the  consumption  of  i  cubic  meter  of  the  gas. 

The  latent  heat  of  steam  may  be  explained  thus:  when  water 
passes  from  a  liquid  state  to  that  of  a  vapor,  it  requires  a  large 
amount  of  heat  to  bring  about  the  transition,  and  this  heat  does 
not  at  all  raise  the  temperature  of  the  substance,  but  is  all 
expended  in  converting  the  water  at  2i2°F.  into  steam  at  the 
same  temperature.  This  particular  amount  is  called  the  latent 
heat  of  steam,  and  is  equal  to  536  calories.  Conversely,  when 
steam  at  2i2°F.  condenses  to  water  at  the  same  temperature, 
536  calories  are  given  off,  and  it  is  this  factor  which  will  be  con- 
sidered under  the  head  of  "net"  calorific  values. 

Gas  calorimeters,  or  instruments  for  determining  heating 
values,  may  be  divided  into  two  broad  classes,  according  as  (i) 
they  do  or  (2)  do  not  measure  the  rise  in  temperature  of  a  known 
quantity  of  water,  caused  by  the  combustion  of  a  measured 
volume  of  gas. 

1  The  Kg.-calorie  is  usually  written  with  a  capital  C,  thus,  Calorie,  while  the  gram- 
calorie  is  written  with  a  small  c.  The  latter  is  also  sometimes  referred  to  as  the 
small  calorie,  while  the  Kg.-calorie  is  known  as  the  large  calorie. 


UNIVERSITY 

OF 


THE    JUNKER   AND    BOYS    CALORIMETERS 


199 


Class  2  is  mostly  composed  of  recent  inventions  which  have 
not  been  carefully  tested,  while  class  i  contains  the  more  accu- 
rate and  reliable  instruments,  and  the  ones  which  are  recom- 
mended for  general  use.  Of  these  there  are  but  four  which  are 
worthy  of  attention,  the  Junker,  the  Simmance-Abady,  the 
Sargent,  and  the  Boys. 


Fig.  30.     Junker  Calorimeter. 

The  Junker  calorimeter  (Fig.  30)  consists  of  a  combustion 
chamber  surrounded  by  an  annular  copper  vessel  filled  with  a 
large  number  of  copper  tubes.  The  gas  is  burned  in  a  long- 
tube  Bunsen  burner,  h,  which  projects  well  into  the  combustion 
chamber  and  is  secured  in  place  by  the  clamp,  i,  fastened  to  the 
metal  rod,  j.  The  burner  is  provided  with  a  spreader  on  top, 
an  adjustable  air  mixer,  and  a  stopcock  for  regulation,  of  the 


200  GAS  AND   GAS   METERS 

gas.  Both  the  air  and  gas  regulators  are  easily  accessible  when 
the  burner  is  in  place.  The  cold  water  enters  at  a,  and  over- 
flowing into  the  cup,  k,  passes  down  through  the  metallic  tube,  /, 
to  the  regulator,  e,  where  the  rate  of  flow  is  controlled.  From 
here  it  flows  upward  around  the  copper  tubes  and  escapes 
through  the  outlet,  c,  into  the  sink  or  the  receiving  vessel. 

The  products  of  combustion  pass  downwards  through  the 
copper  pipes  and  escape  at  m,  where  there  is  a  regulating  damper. 
Since  these  copper  tubes  are  always  surrounded  by  water,  the 
heat  developed  by  combustion  is  removed  by  the  latter,  and  the 
gases  escape  at  the  room  temperature,  while  the  outlet  water  has 
received  all  of  the  heat  generated  by  the  burning  of  the  gas.  N 
is  a  tube  for  the  escape  of  the  water  of  condensation. 

The  entire  instrument  is  nickel-plated  and  mounted  on  three 
legs  provided  with  leveling  screws.  Thermometers  are  inserted, 
by  means  of  rubber  stoppers,  at  0,  p  and  q,  and  thus  the  tempera- 
ture of  the  inlet  and  outlet  water  and  of  the  outlet  gases  may  be 
taken.  As  accessories,  the  following  pieces  of  apparatus  are 
needed :  a  wet  meter,  a  governor,  a  vessel  of  known  capacity  and 
holding  i  to  2  liters,  and  a  50  c.c.  graduated  glass  cylinder. 

The  cost  of  the  meter,  governor  and  calorimeter  is  $200;  these 
may  be  procured  of  Eimer  &  Amend  of  New  York;  but  the 
meter  which  they  furnish  is  unsatisfactory.  The  author  has 
used  a  small  wet  meter  made  to  order  by  the  American  Meter 
Company  and  having  a  dial  divided  into  thousandths  of  a  cubic 
foot.  This  meter  costs  $30,  and  has  given  excellent  satisfaction. 
Readings  are  made  to  within  a  few  ten  thousandths  of  a  foot,  and 
a  table  of  corrections  has  been  drawn  up  for  all  rates  between  three 
and  four  feet  per  hour.  It  is  not  accurate,  however,  at  higher 
rates,  and  where  a  calorimeter  is  to  be  set  up  permanently  in  one 
place,  a  6-foot  wet  meter  registering  i/io  cubic  foot  per  revo- 
lution is  to  be  recommended;  the  cost  of  such  is  $50.  Whatever 
style  of  meter  is  adopted,  it  must  be  carefully  tested  and  the 
water  line  marked  with  great  accuracy.  If  a  governor  is  used, 
one  of  the  wet  style  should  be  employed,  and  it  should  be  placed 
between  the  meter  and  the  burner. 


THE  JUNKER  AND  BOYS  CALORIMETERS       2OI 

Rubber  tubing  is  not  suitable  for  the  transmission  of  the  gas 
on  account  of  the  absorption  of  illuminants  which  it  causes; 
the  writer  has,  however,  found  by  experiment,  that  such  absorp- 
tion has  a  far  less  effect  on  the  calorific  determinations  than  it 
does  on  the  candlepower.  Flexible  metallic  tubing  may  be 
obtained  for  about  9  cents  per  foot,  and  this  will  give  excellent 
satisfaction. 

The  thermometers  used  should  register  degrees  Fahrenheit 
and  should  be  of  the  greatest  accuracy.  Whenever  possible  it  is 
well  to  purchase  those  which  have  been  certified  by  the  National 
Bureau  of  Standards.  If,  for  any  reason,  such  certification  can- 
not be  procured,  the  thermometers  should  be  tested  by  the  oper- 
ator, to  see  that  they  register  exactly  the  same  under  similar 
conditions.  If  a  complete  calibration  is  impossible,  they  should  at 
least  be  immersed  in  ice  water  and  in  boiling  water,  and  observed 
to  see  if  they  register  32  degrees  and  212  degrees  respectively. 
It  is  also  easy  to  compare  their  readings  on  a  few  intermediate 
points  by  heating  water  to  a  definite  temperature,  say  90  degrees, 
immersing  the  thermometers  therein  and  observing  whether  their 
readings  are  the  same.  Small  reading  glasses  are  provided  with 
the  thermometers  measuring  the  temperature  of  the  inlet  and  out- 
let water;  with  these  it  is  comparatively  easy  to  read  to  hundred ths 
of  a  degree. 

A  2-liter  cylinder  is  usually  supplied  for  catching  and  measuring 
the  outlet  water  during  a  determination.  This  is  open  to  criti- 
cism along  several  lines;  the  main  objection,  however,  is  that  it 
is  impossible  to  accurately  determine  the  end  point,  because  of 
the  large  cross-section  exposed.  The  writer  at  first  employed  a 
2  L.  flask,  with  the  calibration  mark  on  the  neck.  This  enabled 
one  to  make  a  very  accurate  reading,  since  in  the  narrow  neck  of 
the  flask  a  difference  of  2  c.c.  was  readily  perceptible;  but  the 
flask  was  fragile,  and  after  one  or  two  had  been  broken,  a  2-liter 
bottle  of  clear  white  glass  was  substituted,  a  scratch  made  on 
the  neck,  and  the  contents  of  the  bottle  up  to  this  point  accurately 
determined.  This  has  proven  most  satisfactory;  the  bottle  is 
strong,  cheap,  can  be  readily  replaced  in  almost  any  drug  store, 


2O2  GAS   AND    GAS   METERS 

and  enables  readings  to  be  made  which  are  easily  accurate  to 
less  than  o.i  per  cent. 

The  Junker  calorimeter  in  use  by  the  Public  Service  Commis- 
sion of  New  York  must  of  necessity  be  so  packed  that  it  can  be 
readily  and  safely  transported;  to  this  end  the  legs  are  unscrewed 
and  done  up  in  canvas  to  keep  them  from  rolling  about;  the 
thermometers  in  their  cases  are  thrust  into  pockets  in  a  canvas 
bag  which  in  turn  is  rolled  up  and  tied;  the  long  inlet  tube  and 
overflow  is  unscrewed  and  fastened  to  the  side  of  a  suit  case  by 
straps.  The  body  of  the  calorimeter  is  laid  on  a  padded  bed  in 
the  bottom  of  the  case,  and  held  in  place  by  three  straps. 
Another  strap  surrounds  the  meter,  and  still  another  holds  the 
burner  in  place.  All  of  the  other  accessories,  such  as  heating 
coil,  bottle,  graduate,  etc.,  are  carried  in  a  second  case. 

In  setting  up  the  instrument,  the  legs  are  first  screwed  in  place 
and  the  inlet  tube  and  waste-gas  pipe  connected.  The  calorim- 
eter is  then  leveled  by  means  of  the  screws  at  the  base  of  the 
legs,  a  small  iron  level  being  always  carried  with  the  outfit. 
Next  the  meter  is  set  up,  leveled  and  filled  with  water  to  a  point 
slightly  above  the  mark  on  the  gauge  glass.  The  gas  is  con- 
nected to  the  inlet  of  the  meter,  the  outlet  being  connected  through 
the  governor  with  the  burner,  the  latter  being  stood  upon  the 
bench. 

The  gas  is  turned  on  and  lighted  at  the  burner,  and  allowed 
to  burn  for  at  least  two  hours  in  order  to  thoroughly  saturate 
the  tubing  and  the  water  in  the  meter  with  gas.  In  case  the 
small  wet  meter  is  used,  three-quarters  of  an  hour  to  an  hour  will 
be  sufficient  for  this.  If  the  meter  is  to  be  used  again  and  again 
with  the  same  gas,  this  long  period  of  saturation  will  only  be 
necessary  when  fresh  water  is  used  in  the  meter;  even  in  such 
cases,  however,  it  is  desirable  to  burn  the  gas  for  some  time  before 
making  the  test,  in  order  that  the  water  may  acquire  the  tem- 
perature of  the  gas,  and  so  that,  if  the  gas  is  different  in  compo- 
sition from  that  which  last  passed  the  meter,  time  may  be 
allowed  for  the  rectification  of  this  difference. 

During  this  preliminary  run,  the  thermometers  are  placed  in 


THE    JUNKER   AND   BOYS   CALORIMETERS  203 

position,  the  water  supply  connected  to  the  inlet  of  the  calorim- 
eter, and  rubber  tubes  connected  to  the  overflows  of  the  inlet 
and  outlet  water.  The  temperature  of  the  inlet  water  must  be 
as  nearly  as  possible  the  same  as  that  of  the  room;  for  if  the  air 
were  the  warmer  of  the  two,  it  would  impart  some  of  its  heat  to 
the  colder  water,  and  thus  the  rise  in  temperature  as  shown  by 
the  outlet  thermometer  would  not  be  wholly  due  to  the  heat  gen- 
erated by  the  combustion  of  the  gas.  Therefore,  if  the  inlet 
water  be  cold,  some  means  must  be  provided  for  raising  its  tem- 
perature to  that  of  the  surrounding  air. 

Three  methods  adapt  themselves  to  this  purpose:  i.  If  the 
calorimeter  is  to  be  permanently  set  up  in  one  place,  a  perma- 
nent water-supply  tank  with  a  large  horizontal  area  may  be 
affixed  to  the  upper  wall  of  the  room  above  the  calorimeter. 
Such  a  tank,  by  virtue  of  the  large  surface  exposed,  will  allow  the 
water  to  speedily  assume  the  temperature  of  the  room;  the  tank 
should  contain  sufficient  water  to  supply  the  calorimeter  for  one 
day's  tests.  This  is  the  best  of  the  three  methods,  and  should  be 
adopted  wherever  possible. 

2.  If  both  hot  and  cold  water  are  constantly  available,  they 
may  be  connected  together  by  means  of  a  brass  T,  and  the  faucets 
regulated  until  the  temperature  of  the  joint  stream  is  that  of  the 
room.  This  plan  is  open  to  the  objection  (i)  that  the  pressure 
is  liable  to  be  variable,  due  to  the  varying  consumption  by  other 
consumers  on  the  line,  thus  causing  both  the  temperature  and  the 
flow  of  the  inlet  water  to  vary,  and  (2)  that  the  temperature  of 
the  water  is  liable  to  vary,  resulting  in  a  similar  difficulty.  It 
may  happen  that  several  tests  will  be  necessary  before  normal 
conditions  are  obtained,  but  by  the  exercise  of  patience  and  judg- 
ment very  satisfactory  results  may  be  obtained  by  this  method  of 
procedure. 

(3 )  If  only  a  cold  water  supply  is  available,  a  heating  coil  may 
be  inserted  between  the  faucet  and  the  inlet  of  the  calorimeter. 
Such  a  coil  may  be  purchased  for  about  $2,  and  consists  of  a  coil 
of  copper  pipe  surrounded  by  an  iron  jacket  to  prevent  radiation. 
The  coil  is  set  upon  an  iron  tripod  and  is  heated  by  means  of  a 


2O4  GAS   AND   GAS   METERS 

Bunsen  or  Tirrill  burner.  By  careful  regulation  of  the  latter  and 
of  the  faucet,  water  of  any  desired  temperature  may  be  supplied 
to  the  calorimeter. 

This  method,  crude  as  it  appears,  has  many  advantages,  and 
may  be  made  to  operate  with  great  success.  If  the  calorimeter  is 
to  be  used  as  a  portable  instrument  and  set  up  in  various  locali- 
ties, the  heating  coil  often  furnishes  the  only  feasible  method  of 
securing  a  constant  supply  of  water  of  a  given  temperature.  It  is, 
of  course,  subject  to  draughts  and  to  fluctuations  in  the  water 
pressure,  and  for  these  reasons  does  not  compare  in  efficiency 
with  the  overhead  water  tank;  but  for  a  cheap  device,  and  espe- 
cially where  portability  is  an  essential  feature,  it  will  give  good 
satisfaction,  and,  with  care,  furnish  results,  which  are  more  than 
sufficiently  accurate  for  practical  work. 

Having  secured  water  of  the  desired  temperature,  it  is  now 
turned  into  the  calorimeter,  and  the  flow  regulated  so  that  the 
water  overflows  in  both  inlet  and  outlet  cups,  and  passes  off  from 
the  latter  at  a  rate  approximating  100  liters  per  hour.  Before  pro- 
ceeding further,  it  is  necessary  to  test  for  a  leak.  This  is  done  by 
shutting  off  the  gas  at  the  burner  and  watching  the  meter  hand. 
If  the  latter  moves,  a  leak  is  indicated,  and  this  must  be  stopped 
before  continuing  with  the  test. 

If  the  water  in  the  meter  is  now  saturated,  the  burner  is  regu- 
lated to  pass  from  4  to  7  feet  per  hour,  according  to  the  gas  to  be 
tested,  and  the  air  mixer  adjusted  to  give  the  most  efficient  flame. 
This  latter  point  is  reached  when  the  tip  of  the  flame  alone  shows 
a  very  faint  luminosity.  This  adjustment  must  be  made  with 
some  care,  since  an  excess  of  air  will  cool  down  the  flame,  while  a 
deficiency  will  result  in  incomplete  combustion.  Certain  experi- 
ments of  the  writer,  however,  have  seemed  to  indicate  that  the 
inaccuracy  caused  by  improper  regulation  (within  reasonable 
limits)  of  the  air  supply  is  smaller  than  is  commonly  supposed. 

The  burner  is  now  inserted  in  the  combustion  chamber  and 
screwed  firmly  in  place.  It  is  always  well  to  hold  a  mirror 
beneath  the  burner  after  it  is  in  position  to  see  that  the  gas  is  still 
burning  and  that  the  flame  has  the  same  appearance  as  when  in 


THE    JUNKER   AND    BOYS    CALORIMETERS 

the  open  air.  The  burner  tube  should  project  some  5  inches  up 
into  the  chamber,  and  it  is  well  to  so  fix  the  clamp  that  this  dis- 
tance may  always  be  maintained. 

After  a  few  minutes  again  regulate  the  water  so  that  there  shall 
be  a  difference  of  about  15  degrees  between  the  temperatures  of 
the  inlet  and  outlet.  Allow  the  gas  to  burn  in  the  calorimeter  for 
from  20  to  30  minutes  before  commencing  a  test.  If  the  conden- 
sation is  to  be  determined,  wait  until  the  condensate  drops  regu- 
larly from  the  outlet  at  the  base,  then  as  the  meter  hand  passes  o, 
place  the  50  c.c.  graduate  under  the  outlet  tube  and  record  the 
reading  of  the  meter.  Allow  at  least  i  to  2  feet  of  gas  to  be  con- 
sumed before  removing  the  graduate  and  again  reading  the  meter. 
From  the  number  of  c.c.  in  the  graduate  and  the  amount  of  gas 
consumed,  the  heat  represented  by  the  water  of  condensation 
may  be  calculated  in  the  manner  shown  later. 

The  apparatus  is  now  ready  for  a  regular  test,  the  writer's 
procedure  being  as  follows:  Record  first  the  temperature  of  the 
room  and  of  the  gas  in  the  meter,  the  barometric  reading,  and  if 
desired  the  humidity.  Insert  the  tube  from  the  outlet  overflow 
into  the  neck  of  the  2  L.  bottle  and  at  the  same  instant  read  the 
meter  and  start  the  stop  watch. 

Make  as  many  readings  as  possible  of  the  water  thermometers, 
and  at  least  one  or  two  of  the  outlet  gases.  At  the  instant  when 
the  water  in  the  bottle  reaches  the  scratch  on  the  neck,  stop  the 
watch  and  read  the  meter  simultaneously. 

Before  proceeding  with  the  calculations,  a  few  precautions  must 
be  noted,  and  if  some  of  these  seem  to  be  repetitions  of  what  has 
preceded,  it  must  be  set  down  to  their  great  importance,  i.  The 
calorimeter  should  be  set  up  in  a  quiet,  light,  well-ventilated  room, 
free  from  draughts  and  with  a  constant  temperature  between  60 
and  80  degrees.  2.  Sunshine  must  not  be  allowed  to  strike  on  or 
near  the  instrument,  and  proximity  to  windows,  electric  lights, 
burning  gas,  steam  radiators  and  hot-water  pipes  must  be  strictly 
avoided.  3.  The  calorimeter  should  be  so  placed  that  the  over- 
flows may  be  easily  led  into  the  sink,  and  adjustment  of  the  gas, 
water,  etc.,  may  be  readily  made  without  disturbing  the  connections. 


2O6  GAS   AND   GAS   METERS 

4.  The  thermometers  should  be  in  a  good  light  and  in  such  a  posi- 
tion that  reading  is  facilitated,  since  any  unnecessary  movement 
during  the  period  of  test  means  a  draught  upon  the  instrument  and 
corresponding  inaccuracy  of  results.  5.  The  meter  must  be 
adjusted  and  leveled  with  the  utmost  precision;  this  is  one  of  the  most 
essential  requirements  for  accurate  work.  6.  The  water  in  the 
meter  and  the  tubing  must  be  thoroughly  saturated  with  the  gas. 
7.  The  gas  must  be  allowed  to  burn  in  the  calorimeter  at  least 
20  minutes  before  commencing  the  test.  8.  The  water  must  be 
^overflowing  from  both  inlet  and  outlet  weirs;  if  this  is  not  the  case, 
it  will  be  found  that  the  temperature  of  the  outlet  water  will  fluc- 
tuate badly.  9.  Always  test  for  leaks.  10.  Always  have  the  tem- 
peratures of  the  inlet  water,  outlet  gas  and  room  as  nearly  as  possi- 
ble the  same.  n.  Be  careful  not  to  spatter  water  on  the  sides  of 
the  calorimeter,  and  if  this  has  been  done,  wipe  it  off  as  quickly 
and  completely  as  possible.  12.  Keep  the  metallic  surfaces  pol- 
ished, and  entirely  free  from  dirt  and  dust.  13.  Never  place  the 
lighted  burner  in  the  calorimeter  when  the  water  is  not  running 
through  the  latter,  and  never  turn  off  the  water  while  the  burner  is 
lighted  and  in  place.  A  recollection  of  this  will  save  many  ther- 
mometers and  much  time. 

For  the  calculation  of  results  the  following  simple  formulae  may 
be  employed: 

L.  of  water  heated  X  degrees  C. 

^  ™  TT  ,  .    r  rise  in  temperature  X  3.968 

B.T.U.  per  cubic  foot  gas  -  — — — ^ — 

cubic  feet  of  gas  burned  (corrected) 

Heat  of  condensation  _  2.381  X  cubic  centimeter  condensate 
in  B.T.U.  per  cu.  ft.  ~  cu.  ft.  gas  burned  (corrected) 

To  illustrate  this  by  a  concrete  instance :  Content  of  bottle  =  2  L. ; 
average  temperature  of  inlet  water  20.25°  C.;  of  outlet  .water 
34.75°  C.;  of  inlet  gas  69°  F.;  of  outlet  gases  22°  C.;  of  room 
70°  F.;  barometer  30.27  inches.  Length  of  test  3  minutes  5 
seconds;  reading  of  meter  at  start  2.7274;  at  end  2.9189;  gas 
burned  (uncorrected)  0.1915  foot;  condensation  35.4  c.c.  for  2 
feet  of  gas  (uncorrected).  Meter  error  for  rate  used  3.2  per  cent 


THE    JUNKER   AND   BOYS   CALORIMETERS  2O/ 

fast.     Corrections:  Barometer  0.9  per  cent  +  ;  temperature  2.3  per 
cent  —  ;  meter  3.2  per  cent  —  ;  total  4.6  per  cent  — . 

0.1915  4-  1.046  =  0.1831  foot  of  gas  burned  for  B.T.U.  test. 

2.0  -*•  1.046  =  i. 9120  feet  of  gas  burned  for  condensation  test. 
34.75  degrees  -  20.25  degrees  =  14.5  degrees. 
2  X  14.5  X  3.968  =  62g  g  B  T  jj          cubic  foQt 

.1831 

2-3Sl  x  35-4  =44>I  B.T>IL  in  condensation. 

1.912 

628.5  —  44.1  =  584.4  net  B.T.U.  per  cubic  foot  of  gas. 

There  has  been  considerable  discussion  and  disagreement  over 
the  term  "net"  heating  value,  and  the  following  explanation  is 
offered  in  order  that  the  issues  at  stake  may  be  more  clearly  set 
forth.  When  a  gas  containing  hydrogen  is  burned,  water  vapor  or 
steam  is  formed,  and  this  in  condensing  to  a  liquid  gives  off  heat  to 
the  amount  of  536  calories  per  gram.  Now  in  the  calorimeter  this 
heat  goes  towards  raising  the  temperature  of  the  water,  while  in 
industrial  appliances  such  as  Welsbach  mantles,  gas  engines,  gas 
stoves,  etc.,  the  products  of  combustion  pass  off  at  a  temperature 
above  that  at  which  steam  condenses,  and  consequently  the  latent 
heat  is  not  available. 

For  this  reason  it  is  argued  by  many  that  in  order  to  arrive  at  the 
true  heating  value  of  the  gas,  considered  from  a  practical  stand- 
point, this  heat  of  condensation  should  be  deducted  from  the  total 
or  gross  heating  value.  On  the  other  hand,  it  is  being  more  and 
more  strongly  urged  to-day  that  the  true  heating  power  of  a  gas  is 
all  the  heat  that  can  be  extracted  from  its  combustion,  cooling  the 
products  to  the  original  temperature  of  the  gas  and  air;  that  the 
energy  that  a  gas  engine,  for  example,  is  receiving  from  the  com- 
bustion of  a  quantity  of  gas  is  diminished  several  times  as  much  by 
the  sensible  heat  carried  away  in  the  exhaust  at  1000  to  1500°  F., 
as  it  is  by  the  heat  loss  involved  in  the  vaporization  or  condensation 
of  the  water  formed;  that  all  other  fuels  are  rated  according  to  their 
total  heating  value,  and  that  there  is  no  justice  in  discrimination 
against  gas. 


208  GAS   AND   GAS   METERS 

To  quote  from  the  very  able  and  scholarly  committee  of  the 
American  Gas  Institute,  "  If  the  latent  heat  and  sensible  heat  of  the 
condensed  water  from  the  products  of  combustion  are  deducted, 
there  is  just  as  much  reason  for  deducting  the  sensible  heat  of  the 
uncondensed  portion  of  the  products  of  combustion,  since  it  is 
necessarily  lost  at  the  same  time;  and  if  the  temperature  of  the 
exhaust  products  leaving  the  apparatus  is  very  high,  this  sensible 
heat  may  be  several  times  that  deducted  in  obtaining  the  so-called 
'net'  value.  In  other  words,  there  would  be  a  different  true 
'  net '  value  for  each  change  in  conditions  of  the  utilization  of  the 
gas,  and  none  of  them  determinable  by  a  direct  test  by  a  calorimeter 
or  any  other  known  instrument. 

"Therefore  the  committee  are  of  the  opinion  that  the  heating 
value  of  a  gas  should  be  expressed  only  in  that  which  is  determin- 
able as  the  'gross'  or  total  heating  value,  the  value  of  the  gas  as 
given  by  the  calorimeter.  .  .  .  The  argument  for  a  correction  is 
based  on  the  claim  that  all  of  the  heat  developed  cannot  be  utilized, 
but  that  varies  widely  with  the  appliance.  With  some  appliances  a 
great  loss  is  experienced  through  sensible  heat  of  waste  products 
and  latent  heat  of  water  vapors.  With  other  appliances  this  loss  is 
reduced  to  very  small  magnitude,  and  water  heaters,  or  similar  types 
of  appliances,  can  be  made,  as  in  the  calorimeter  itself,  to  utilize  it 
all.  In  what  an  absurd  position  we  would  find  ourselves  if,  advo- 
cating the  use  of  'net'  values,  we  tried  to  figure  the  efficiency  of 
such  an  appliance." 

Regarding  the  situation  purely  from  a  scientific  standpoint,  the 
writer  considers •  that  it  is  no  more  fair  to  state  the  "net"  as  the 
true  heating  value  of  the  gas  than  it  would  be  to  give  the  candle- 
power  taken  with  an  imperfect  lava  tip  burner  as  the  true  candle- 
power  of  the  gas.  The  "net"  results  are  sometimes  interesting 
and  valuable  from  a  practical  standpoint,  but  even  here  it  would 
seem  advisable  to  base  all  calculations  on  the  gross  or  true  heating 
value  of  the  gas,  making  due  allowance  when  necessary  for  the 
heat  of  condensation. 

The  Junker  calorimeter  is  probably  the  most  perfect  instru- 
ment of  its  kind  on  the  market.  Experiments  at  the  University 


THE    JUNKER   AND   BOYS    CALORIMETERS  209 

of  Wisconsin  show  that  the  average  efficiency  of  this  instrument 
is  over  99^  per  cent,  a  truly  remarkable  result.  The  merits  of 
the  Junker  are:  i.  A  polished  metallic  surface,  with  an  air 
chamber  within;  this  arrangement  practically  prevents  radiation. 
2.  The  water  circulates  in  the  opposite  direction  from  the  prod- 
ucts of  combustion,  and  thus  the  colder  water  meets  the  cooler 
gases.  3.  The  water  content  is  only  about  ij  pounds;  while 
this  is  large  enough  for  the  efficient  absorption  of  the  heat  from 
gases  of  high  calorific  values,  it  is  also  small  enough  to  insure 
accuracy  with  gases  of  low  heating  power.  4.  A  constant  head 
of  water  is  always  maintained  by  means  of  weirs.  5.  The  water 
regulator  is  an  arm  swinging  on  a  quadrant,  allowing  delicate 
and  accurate  adjustment  of  the  flow.  6.  The  temperature  of 
inlet  and  outlet  water  is  easily  and  correctly  determined.  7.  The 
instrument  is  portable.  8.  The  air  and  gas  supplies  are  easy  to 
regulate  when  the  burner  is  in  position.  9.  The  condensate 
drains  readily  and  regularly.  10.  The  waste-gas  damper  allows 
of  the  regulation  of  the  air  supply  through  the  calorimeter, 
ii.  The  whole  apparatus  is  well  made  and  easy  to  take  apart 
and  clean. 

There  are  one  or  two  defects  to  the  calorimeter  as  it  is  com- 
monly supplied.  The  meter  which  is  furnished  is  entirely  unsat- 
isfactory, principally  because  it  has  a  fixed  overflow  within  the 
meter,  and  when  the  latter  registers  incorrectly  it  cannot  be 
adjusted  without  taking  it  apart.  The  thermometers  in  the  inlet 
and  outlet  water  are  not  on  the  same  level ;  this  renders  it  difficult 
to  read  them  both,  and  the  movement  of  the  operator  in  making 
readings  is  liable  to  cause  a  draught.  The  water  is  measured 
instead  of  being  weighed,  and  the  latter  method  is  regarded  by 
many  as  the  more  accurate  and  satisfactory. 

The  Committee  of  the  American  Gas  Institute  considers  that 
the  mounting  of  the  instrument  on  three  legs  makes  it  somewhat 
unstable,  and  that  it  is  rather  difficult  to  insert  the  lighted  burner 
when  the  instrument  is  set  up;  but  the  writer  has  experienced  no 
trouble  in  either  of  these  directions.  The  thermometers  are  of 
the  centigrade  type,  and  the  water  is  measured  in  cubic  centi- 


210  GAS   AND    GAS   METERS 

meters;   in  order  to  express  the  results  in  B.T.U.  as  is  customary 
in  this  country,  it  is  necessary  to  make  an  extra  calculation. 

Most  if  not  quite  all  of  these  difficulties  may  be  easily  reme- 
died. Scales  sensitive  to  o.oi  of  a  pound  may  be  procured  and 
used  in  conjunction  with  a  copper  pail  to  replace  the  graduate  or 
bottle  for  measuring  the  water.  It  should  be  noted,  however, 
that  while  the  limit  of  accuracy  of  the  scales  is  4.5  g.,  experiments 
with  the  bottle  mentioned  have  shown  that  an  error  of  4  g.  is 
almost  impossible,  and  the  average  error  is  about  i  to  2  g. 

In  purchasing  the  instrument,  it  should  be  distinctly  specified 
that  Fahrenheit  thermometers  are  desired,  and  that  the  meter 
will  be  purchased  separately.  The  thermometers  may  be  brought 
to  the  same  level  by  a  very  simple  device  in  use  in  the  laboratory 
of  the  Milwaukee  Gas  Company  and  shown  so  clearly  in  Fig.  31 l 
that  no  further  description  seems  necessary.  With  these  changes 
it  will  be  difficult  to  find  fault  with  the  instrument  along  any 
line. 

The  Boys  Calorimeter  is  the  official  instrument  in  London,  and 
the  following  description  thereof  is  taken  from  "The  Notification 
of  the  Metropolitan  Gas  Referees  for  the  year  1908."  This  calo- 
rimeter, which  has  been  designed  by  Mr.  Boys,  is  shown  in  ver- 
tical section  (Fig.  32).  "It  consists  of  three  parts,  which  may  be 
separated,  or  which,  if  in  position,  may  be  turned  relatively  to 
one  another  about  their  common  axis.  The  parts  are  (i)  the 
base,  A,  carrying  a  pair  of  burners,  B,  and  a  regulating  tap.  The 
upper  surface  of  the  base  is  covered  with  a  bright  metal  plate 
held  in  place  by  three  centering  and  lifting  blocks,  C.  The  blocks 
are  so  placed  as  to  carry  (2)  the  vessel,  D,  which  is  provided  with 
a  central  copper  chimney,  E,  and  a  condensed  water  outlet,  F. 

"  Resting  upon  the  rim  of  the  vessel,  D,  is  (3)  the  water-circulat- 
ing system  of  the  calorimeter  attached  to  the  lid,  G.  Beginning 
at  the  center  where  the  outflow  is  situated,  there  is  a  brass  box 
which  acts  as  a  temperature-equalizing  chamber  for  the  outlet 
water.  Two  dished  plates  of  thin  brass, ^KK,  are  held  in  place 
by  three  scrolls  of  thin  brass,  LLL.  These  are  simply  strips  bent 

1  American  Gas  Institute. 


THE    JUNKER   AND   BOYS    CALORIMETERS 


211 


round  like  unwound  clock  springs,  so  as  to  guide  the  water  in  a 
spiral  direction  inwards,  then  outwards  and  then  inwards  again 
to  the  outlet. 


Fig.  31.     Modified  Junker  Calorimeter. 

"  The  lower  or  pendant  portion  of  the  box  is  kept  cool  by  circu- 
lating water,  the  channel  for  which  may  be  made  in  the  solid  metal, 
as  shown  on  the  right  side,  or  by  sweating  on  a  tube  as  shown  on  the 
left.  Connected  to  the  water  channel  at  the  lowest  point  by  a  union 
are  five  or  six  turns  of  copper  pipe,  such  as  is  used  in  a  motor  car 


212 


GAS   AND    GAS   METERS 


ife- 


Millimeters 
==L    Inches 


Fig.  32.     Boys  Calorimeter. 


THE    JUNKER   AND   BOYS    CALORIMETERS  213 

radiator  of  the  kind  known  as  Clarkson's.  In  this  a  helix  of  copper 
wire  threaded  with  copper  wire  is  wound  around  the  tube,  and  the 
whole  is  sweated  together  by  immersion  in  a  bath  of  melted  solder. 
A  second  coil  of  pipe  of  similar  construction  surrounding  the  first 
is  fastened  to  it  at  the  lower  end  by  a  union.  This  terminates  at 
the  upper  end  in  a  block,  to  which  the  inlet  water  box  and  thermom- 
eter holder  are  similarly  secured  above  the  equalizing  chamber,  H. 
The  lowest  turns  of  the  two  coils,  M N,  are  immersed  in  the  water 
which  in  the  first  instance  is  put  into  the  vessel,  D. 

"  Between  the  outer  and  inner  coils,  MN,  is  placed  a  brattice,  Q, 
made  of  thin  sheet  brass,  containing  cork  dust  to  act  as  a  heat 
insulator.  The  upper  annular  space  in  the  brattice  is  closed  by 
a  wooden  ring,  and  that  end  is  immersed  in  melted  rosin  and 
beeswax  cement,  to  protect  it  from  any  moisture  which  might 
condense  upon  it.  The  brattice  is  carried  by  an  internal  flange, 
which  rests  upon  the  lower  edge  of  the  casting,  H.  A  cylindrical 
wall  of  thin  sheet  brass,  a  very  little  smaller  than  the  vessel,  D,  is 
secured  to  the  lid  so  that  when  the  instrument  is  lifted  out  of  the 
vessel  and  placed  upon  the  table,  the  coils  are  protected  from 
injury.  The  narrow  air  space  between  this  and  the  vessel,  D,  also 
serves  to  prevent  interchange  of  heat  between  the  calorimeter  and 
the  air  of  the  room. 

"  The  two  thermometers  for  reading  the  water  temperatures,  and 
a  third  for  reading  the  temperature  of  the  outlet  air,  are  all  near 
together  and  at  the  same  level.  The  lid  may  be  turned  round  into 
any  position  relatively  to  the  gas  inlet  and  condensed  water  drip 
that  may  be  convenient  for  observation,  and  the  inlet  and  outlet 
water  boxes  may  themselves  be  turned  so  that  their  branch  tubes 
point  in  any  direction. 

"  A  regular  supply  of  water  is  maintained  by  connecting  one  of 
the  two  outer  pipes  of  the  overflow  funnel  to  a  small  tap  over  the 
sink.  The  overflow  funnel  is  fastened  to  the  wall  about  i  meter 
above  the  sink,  and  the  outer  pipe  is  connected  to  a  tube  in  which 
there  is  a  diaphragm  with  a  hole  about  2.3  mm.  in  diameter.  This 
tube  is  connected  to  the  inlet  pipe  of  the  calorimeter.  A  piece  of 
stiff  rubber  pipe  long  enough  to  carry  the  outflow  water  clear  of  the 


214  GAS   AND    GAS   METERS 

calorimeter  is  slipped  on  to  the  outflow  branch,  and  the  water  is 
turned  on  so  that  a  little  escapes  by  the  middle  pipe  of  the  overflow 
funnel  and  is  led  by  a  third  piece  of  tube  into  the  sink.  The 
amount  of  water  that  passes  through  the  calorimeter  in  four 
minutes  should  be  sufficient  to  fill  the  graduated  vessel  to  some 
point  above  the  lowest  division,  but  insufficient  in  five  minutes  to 
come  above  the  highest  division.  If  this  is  not  found  to  be  the 
case,  a  moderate  lowering  of  the  overflow  funnel  or  reaming  out 
of  the  hole  in  the  diaphragm  will  make  it  so.  The  overflow  funnel 
should  be  provided  with  a  lid  to  keep  out  dust. 

"  The  thermometers  for  reading  the  temperature  of  the  inlet  and 
outlet  water  should  be  divided  on  the  Centigrade  scale  into  tenths 
of  a  degree,  and  they  should  be  provided  with  reading  lenses  and 
pointers  that  will  slide  upon  them.  The  thermometers  are  held 
in  place  by  corks  fitting  the  inlet  and  outlet  water  boxes.  The 
positions  of  these  thermometers  should  be  interchanged  every 
month.  The  thermometers  for  reading  the  temperature  of  the 
air  near  the  instrument  and  the  effluent  gas  should  be  divided  on 
the  Centigrade  scale  into  degrees. 

"The  flow  of  air  to  the  burners  is  determined  by  the  degree  to 
which  the  passage  is  restricted  at  the  inlet  and  at  the  outlet.  The 
blocks,  C,  which  determine  the  restriction  at  the  inlet  are  made 
of  metal  three-sixteenths  of  an  inch  or  about  5  mm.  thick,  while 
the  holes  round  the  lid  which  determine  the  restriction  at  the 
outlet  are  five  in  number  and  are  five-eighths  of  an  inch  or  16  mm.  in 
diameter.  The  thermometer  used  for  finding  the  temperature  of 
the  effluent  gas  is  held  by  a  cork  in  the  sixth  hole  in  the  lid  so  that 
the  bulb  is  just  above  the  upper  coil  of  pipe. 

"  The  calorimeter  should  stand  on  a  table  by  the  side  of  a  sink 
so  that  the  condensed  water  and  hot  water  outlets  overhang  and 
deliver  into  the  sink.  A  suitable  change-over  funnel  may  be 
constructed  as  follows :  a  piece  of  India-rubber  tube  reaching  nearly 
to  the  base  should  be  attached  to  the  waste-water  pipe  so  as  to 
avoid  splashing,  and  another  piece  may  conveniently  be  slipped  on 
to  the  condensed  water  outlet  so  as  to  lead  the  condensed  water 
into  a  flask,  but  care  should  be  taken  that  the  small  side  hole  is 


THE    JUNKER   AND   BOYS   CALORIMETERS  21$ 

not  covered  by  the  tube.  A  glass  vessel  must  be  provided, 
of  the  size  of  the  vessel,  D,  containing  water  in  which  is  dis- 
solved sufficient  carbonate  of  soda  to  make  it  definitely 
alkaline. 

"The  calorimeter  after  use  is  lifted  out  of  its  vessel,  D,  and  placed 
in  the  alkaline  solution  and  there  left  until  it  is  again  required  for 
use.  The  liquid  should  not,  when  the  calorimeter  is  placed  in  it, 
come  within  2  inches  of  the  top  of  the  vessel.  The  liquid  must 
be  replenished  from  time  to  time,  and  its  alkalinity  must  be 
maintained." 

The  Gas  Referees  have  made  a  special  study  of  this  instrument, 
and  their  reputation  for  careful,  accurate  and  progressive  work  is 
well  known ;  on  this  account,  and  also  because  of  the  fact  that  the 
Boys  calorimeter  is  but  little  known  or  used  in  this  country,  it 
seems  justifiable  to  insert  here  the  Referees'  own  description  of 
the  method  by  which  this  apparatus  is  to  be  used. 

"In  order  to  test  the  gas  for  calorific  power,  the  gas  shall  first 
pass  through  a  meter  and  a  balance  governor  of  the  same  construc- 
tion as  those  on  the  photometer  table.  It  shall  then  be  led  to  the 
gas  inlet  in  the  base  of  the  calorimeter.  The  gas  shall  be  turned 
on  and  lighted,  and  the  tap  of  the  calorimeter  shall  be  so  adjusted 
as  to  allow  the  meter  hand  to  make  one  turn  in  from  60  to  75 
seconds.  The  water  shall  be  turned  on  so  that  when  the  regular 
flow  through  the  calorimeter  has  been  established  a  little  may 
pass  the  overflow  of  the  funnel  and  trickle  over  into  the  sink. 
Water  must  be  poured  in  through  one  of  the  holes  in  the  lid  until 
it  begins  to  run  out  at  the  condensation  outlet.  The  calorimeter 
may  then  be  placed  upon  its  base. 

"The  measuring  vessel  carrying  the  change-over  funnel  shown 
in  Figs.  1 6  and  18,  pp.  42  and  43  *,  should  then  be  placed  in  position 
in  the  sink  so  that  the  outlet  water  is  led  into  the  sink.  The  hot 
water  outlet  tube  of  the  calorimeter  should  be  above  but  should 
not  touch  the  change-over  funnel.  After  an  interval  of  not  less 
than  30  minutes,  the  Gas  Examiner,  after  bringing  the  reading 
glasses  into  position  on  the  thermometers  used  for  measuring  the 

i  See  Notif.  Met.  G.  Ref.  1908. 


2l6  GAS   AND    GAS    METERS 

temperature  of  the  inlet  and  outlet  water,  shall  then  make  the 
following  observations : 

"  When  the  meter  hand  is  at  75  he  shall  read  the  inlet  tempera- 
ture; when  it  reaches  100  he  shall  move  the  funnel  so  as  to  direct 
the  outflow  into  the  measuring  vessel  and  at  the  same  time  he 
shall  start  the  stop-clock  or  a  stop-watch.  When  the  meter  hand 
reaches  25  he  shall  make  the  first  reading  of  the  outlet  temperature. 
He  shall  continue  to  read  the  outlet  temperature  at  every  one- 
quarter  turn  until  15  readings  have  been  taken.  The  meter  hand 
will  then  be  at  75.  He  shall  also  at  every  turn  of  the  meter  except 
the  last  make  a  reading  of  the  inlet  temperature  when  the  meter 
hand  is  between  75  and  100. 

"  When  the  meter  hand  reaches  100  after  the  last  outlet  tempera- 
ture has  been  read,  the  Gas  Examiner  shall  shift  the  funnel  so  as 
to  direct  the  outlet  water  into  the  sink  again  and  at  the  same  time 
stop  the  clock  or  watch.  The  barometer  and  the  thermometers 
showing  the  temperatures  of  the  effluent  gas,  of  the  air  near  the 
calorimeter  and  of  the  gas  in  the  meter,  shall  then  be  read.  The 
time  shown  by  the  stop-clocks  shall  be  recorded. 

"  The  mean  of  the  four  readings  of  the  inlet  temperature  is  to  be 
subtracted  from  the  mean  of  the  fifteen  readings  of  the  outlet 
temperature,  and  the  difference  is  to  be  multiplied  by  3  and  by 
the  number  of  liters  of  water  collected,  and  the  product  is  to  be 
divided  by  the  tabular  number.  The  difference  in  degrees  Centi- 
grade of  the  temperature  of  the  effluent  gas  and  of  the  surround- 
ing air  shall  be  taken,  and  one-sixth  of  this  difference  shall  be 
added  to  the  result  previously  found  if  the  effluent  gas  is  the 
warmer  of  the  two,  or  subtracted  if  the  effluent  gas  is  the  colder 
of  the  two.1  The  result  is  the  gross  calorific  power  of  the  gas  in 
Calories  per  cubic  foot. 

"  In  addition  to  the  observations  described,  the  amount  of  con- 
densed water  resulting  from  the  combustion  of  the  gas  shall  be 
measured.  For  this  purpose  the  condensation  water  shall  be  led 
into  a  flask  not  less  than  20  minutes  after  the  calorimeter  has 
been  placed  in  position.  The  amount  collected  in  not  less  than 

1  This  correction  has  been  found  by  experiment. 


THE    JUNKER   AND    BOYS    CALORIMETERS  2I/ 

30  minutes  shall  be  measured,  the  time  of  collection  having  been 
accurately  noted. 

"  The  number  of  cubic  centimeters  collected  shall  be  multiplied 
by  the  number  of  seconds  in  the  time  indicated  by  the  stop-clock  and 
by  the  number  1.86.  The  number  of  seconds  in  the  time  during 
which  the  condensed  water  was  being  collected  shall  be  multiplied 
by  the  tabular  number.  The  first  product  shall  be  divided  by 
the  second.  The  quotient  is  to  be  subtracted  from  the  gross 
calorific  power.  The  difference  is  the  net  calorific  power  in  Calories 
per  cubic  foot.  The  gross  and  net  calorific  power  in  B.T.U.  can  be 
obtained  by  multiplying  the  corresponding  number  of  Calories 
by  3.968." 

While  accurate  results  can  doubtless  be  obtained  with  this 
instrument  under  certain  circumstances,  it  is  not  a  convenient  form 
to  operate,  and  cannot  be  recommended  for  use  in  this  country. 
The  Committee  on  Calorimetry  of  the  American  Gas  Institute 
made  a  careful  study  of  the  Boys  calorimeter  and  found  several 
defects  or  undesirable  points  therein. 

The  water  content  is  only  about  0.7  of  a  pound,  or  less  than 
one-half  that  of  the  Junker;  this  necessarily  limits  the  rate  at 
which  the  gas  may  be  burned,  and  renders  the  instrument  unsuit- 
able for  use  with  gases  of  high  calorific  value.  The  meter  registers 
one-twelfth  of  a  cubic  foot  per  revolution,  and  the  water  gauge 
is  of  too  great  a  diameter,  making  it  difficult  to  secure  accurate 
adjustment.  The  pressure  regulator  is  complicated  and  liable  to 
leak.  The  inlet  and  outlet  thermometer  openings  are  too  small, 
and  the  connections  so  short  that  if  the  stopper  be  inserted  firmly 
it  is  liable  to  throttle  the  flow  of  water. 

There  is  no  way  of  regulating  the  amount  of  air  passing 
through  the  instrument,  and  if  any  adjustments  become  necessary 
on  the  burner  or  the  rest  of  the  apparatus,  the  operator  is  obliged 
to  lift  off  the  heavy  coil  and  place  it  on  some  specially  arranged 
support;  it  cannot  be  moved  far  without  disturbing  the  water 
connections. 

The  burner  provided  gives  a  luminous  flame,  and  this  is 
decidedly  undesirable,  since  with  the  rich  gases  so  often  found 


218  GAS   AND    GAS    METERS 

in  the  United  States,  it  would  smoke  badly,  and  thus  deposit 
carbon  on  the  water  coils.  The  use  of  the  luminous  flame  was 
intended  to  aid  the  observer  in  seeing  that  it  was  always  alight, 
but  this  end  may  be  accomplished  by  other  and  better  means. 

In  order  to  make  more  than  one  run,  it  is  necessary  to  lift  out 
the  coil  and  shut  off  the  water,  since  the  device  for  shifting  the 
water  into  the  glass  graduate  is  mounted  on  the  latter.  Last, 
but  not  least,  the  calorimeter  must  be  taken  apart  in  order  to 
light  or  extinguish  the  burner.  The  price  of  the  entire  appara- 
tus in  England  is  about  $61;  delivered  in  the  United  States  it 
would  probably  cost  nearer  $75  to  $90. 


CHAPTER  II. 
OTHER  INSTRUMENTS  AND  METHODS. 

THE  Simmance-Abady  calorimeter  is,  like  the  Boys,  of  Eng- 
lish origin,  and  is  seldom  used  in  this  country.  Figs.  33  and 
34  show  the  construction  in  detail.  In  Fig.  33,  A'  is  the  water 
inlet,  whence  the  water  passes  through  cock,  A,  and  fills  water 
level  tube,  K  (for  enabling  the  regularity  of  pressure  to  be  seen 
at  a  glance),  flows  round  bulb  of  thermometer,  D  (the  ther- 
mometer being  in  Centigrade  degrees,  divided  into  tenths  and 
arranged  in  a  magnifying  tube,  to  enable  the  height  of  the  mer- 
cury column  to  be  readily  perceived),  and  along  the  course  shown 
by  arrows  through  the  annular  chambers,  EEEE,  down  tubes, 
FFFF,  and  up  through  tubes,  G'G' ',  past  the  baffle  plate  into 
upper  receptacle,  H',  round  bulb  of  thermometer,  /,  which  is 
similar  to  the  thermometer,  D,  and  thence  by  outlet,  G.  The 
heated  water  is  discharged  to  waste,  or,  by  turn  of  cock  or  tilt  of 
bucket,  into  graduated  measure,  M1 ',  which  is  subdivided  into 
2  c.c.,  and  has  a  capacity  of  about  1000  c.c. 

The  products  of  combustion  pass  up  center  shaft,  N',  and, 
partially  condensing  in  chamber,  O',  drop  down  annular  passage, 
MMMMj  and  issue,  being  reduced  to  the  temperature  of  the 
original  fuel,  which  should  be  the  same  as  the  inlet  water  and 
approximate  to  the  air  of  the  room,  as  carbonic  acid,  non-con- 
densible  products  and  water,  at  lip  p.  A  shutter  is  provided 
by  which  the  flow  of  the  products,  and  therefore  their  tempera- 
ture at  point  of  issue,  can  be  regulated,  and  the  result  registered 
on  a  thermometer  provided  for  the  purpose. 

The  condensed  water  is  collected  in  the  graduated  measure,  R,  for 
purpose  of  the  deduction  to  be  made  upon  gross  results.  5  is  the 
Bunsen  burner  for  burning  gaseous  fuels,  a  special  lamp  and 
balance  being  provided  for  liquid  fuels. 

219 


22O 


GAS   AND    GAS   METERS 


Fig.  33.     Simmance-Abady  Calorimeter. 
Sectional  View. 


OTHER   INSTRUMENTS   AND   METHODS  .  221 

To  fit  up  calorimeter,  the  stand  is  placed  on  a  firm,  level  base, 
and  the  calorimeter  is  placed  thereon,  with  the  inlet  cock  con- 
venient to  the  water  supply.  The  two  large  thermometers  are 
slipped  carefully  (after  being  wetted)  through  the  rubber  stop- 
pers already  placed  in  the  sockets,  D  and  J,  the  glass  tube  being 
put  into  the  remaining  socket.  The  two  thermometers  and 
water-level  tube  stand  side  by  side,  and  the  observation  of  their 
indications  is  thus  facilitated. 

The  correct  and  rapid  observation  of  the  inlet  and  outlet  ther- 
mometers and  of  the  water  level  is,  as  will  be  seen  hereafter,  a 
most  important  point.  The  thermometers  should  be  carefully 
tested,  and  any  slight  difference  in  their  readings  under  like  con- 
ditions noted.  They  indicate  in  tenths  of  a  degree  Centigrade, 
and  are  very  sensitive;  they  require  very  careful  handling,  and 
once  in  their  places  should  not  be  disturbed. 

The  inlet  cock  is  connected  to  the  water  supply,  which  should 
be  such  as  to  provide  a  constant  head.  The  outlet,  G,  is  con- 
nected by  a  length  of  rubber  tube  to  a  convenient  waste  service. 
The  burner  is  connected  by  rubber  tube  to  a  gas  supply,  which 
should  be  such  as  to  provide  a  constant  pressure.  The  gas  is 
measured  by  an  experimental  meter,  which  should  be  in  such  a 
position  as  to  be  easily  read  by  an  operator  working  the  water 
outlet  of  calorimeter.  The  products  outlet  thermometer  is  placed 
in  the  rubber  stopper  provided  for  that  purpose.  The  proper 
appreciation  of  readings  on  this  thermometer  is  important.  The 
small  glass  measure  is  placed  at  the  condensation  outlet.  The 
large  glass  measure  is  placed  at  the  water  outlet  of  calorimeter. 

To  Test  Calorimeter.  Turn  on  the  water  gently  until  it  rises 
almost  to  the  top  of  the  glass  tube,  while  it  is  flowing  to  waste  at 
the  outlet  of  calorimeter.  Close  the  top  of  the  glass  tube,  in- 
crease the  water  flow  and  let  it  run  for  one  or  two  minutes.  This 
is  only  necessary  when  the  calorimeter  is  first  fitted  up.  See  that 
all  joints  are  sound,  and  then  unstop  the  glass  tube,  and  reduce 
the  water  flow  until  it  stands  at  about  one-half  way  up  the  tube. 
Mark  the  meniscus  by  a  rubber  ring  slipped  round  the  glass 
tube. 


222 


GAS   AND   GAS   METERS 


To  make  a  Test.  Observe  the  water  level  and  see  that  it  is  con- 
stant. If  the  water  supply  varies  the  water  level  in  the  tube  will 
vary.  If  an  accurate  test  is  required  it  should  remain  at  the  observed 


Iilliiliiiiiiii!iiii!lii!iiiiiii;:;..:. ^~~ ;•••         

Fig.  34.     Simmance-Abady  Calorimeter. 

point.  Light  gas  burner  outside  calorimeter,  put  it  under  calorim- 
eter and  lift  it  until  the  stand  can  be  slid  beneath  it.  See  that  the 
burner  rests  in  the  space  prepared,  when  it  will  be  central  with  the 
central  shaft,  N'.  A  small  mirror  will  enable  the  operator  to  see 


OTHER   INSTRUMENTS    AND    METHODS  223 

how  the  flame  is  burning.  Let  the  gas  burn  (having  adjusted  its  rate 
and  being  assured  of  its  regularity),  allow  the  water  to  run  until 
the  outlet  water  thermometer,  which  will  have  risen  as  the  water  has 
absorbed  the  heat,  has  again  become  constant.  Adjust  the  products 
outlet  door  until  the  temperature  of  the  issuing  products  is  the  same 
as  the  inlet  water.  Observe  the  temperature  of  the  gas  and  of  the 
atmosphere.  The  operator  should  endeavor  to  work  under  such 
conditions  that  the  temperature  of  atmosphere,  gas  and  inlet  water 
approximate.  Also  watch  the  reading  of  the  barometer.  Having 
effected  the  adjustment  of  the  products  outlet,  watch  both  the  water 
thermometers  for  a  few  seconds.  See  they  are  constant,  and  note 
the  difference,  adding  or  deducting  any  observed  differences  in  ther- 
mometers when  tested  as  described. 

As  the  meter  hand  (an  ordinary  photometer  meter  is  assumed) 
passes  a  division,  say  o,  turn  the  outlet  water,  which  has  been  run- 
ning to  waste,  into  the  tall  cubic  centimeter  measure,  and  as  the 
meter  hand  passes  a  second  marked  division  (say  12),  switch  the 
water  back  to  waste.  Read  on  the  scale  of  the  glass  measure 
the  quantity  of  water  run  in  the  interval.  Repeat  the  operation 
(which  will  take  a  few  seconds  only)  twice,  and  take  the  mean  of  the 
three  readings.  The  tall  measure  is  emptied  for  each  reading.  The 
above  description  is  adapted  from  the  account  of  one  of  the  inven- 
tors of  the  instrument,  Dr.  Jacques  Abady. 

Calculations.  The  readings  of  the  inlet  and  outlet  thermometers 
are  to  be  averaged  and  the  former  result  subtracted  from  the  latter. 
The  mean  of  the  three  readings  of  the  meter  gives  the  amount  of 
gas  consumed;  while  the  quantity  of  water  heated  is  judged  from 
the  average  of  the  three  readings  of  the  glass  cylinder.  Assume  the 
average  temperature  of  the  inlet  water  to  be  15.4  degrees,  of  the 
outlet  water  25.2  degrees,  gas  burned  0.0228  foot  uncorrected,  water 
heated  350  c.c.  Temperature  inlet  gas  70°  F.;  barometer  29.67. 

Correction  for  temperature    2.5  percent  — 
Correction  for  barometer       1.1  per  cent  — 

3. 6  per  cent  — 
.0228  -T-  1.036  =  .0220  cubic  foot  gas  corrected. 

(25.2  -  15.4)  X  .350  =  I55>0  gross  caiories  per  cubic  foot. 
.022 


224  GAS   AND   GAS   METERS 

To  change  this  to  British  Thermal  Units  per  cubic  foot,  multiply 
by  3.968.  The  heat  due  to  the  condensation  is  calculated  in  the 
same  manner  as  with  the  Junker  calorimeter,  and  the  result  is  to  be 
subtracted  from  the  gross  heat  units,  if  the  "net"  heating  value  is 
desired.  This  calculation  may  be  expressed  by  formula,  thus: 

W  X  T 

H= — — ,  where   T  =  rise  in  temperature  of   the  water, 

G 

H  =  gross  Calories  per  cubic  foot  of  gas,  W  ••=  the  water  heated, 
expressed  in  fractions  of  a  liter,  and  G  =  the  corrected  amount  of 
gas  burned.  The  writer  feels  called  upon  to  protest,  however, 
against  expressing  results  in  this  manner.  The  Calorie,  as  has  been 
stated,  is  the  amount  of  heat  required  to  raise  the  temperature  of 
i  kilogram  of  water  i°  C.  All  of  these  units  are  in  the  metric  sys- 
tem, and  to  speak  of  Calories  per  cubic  foot  is  simply  to  express  part 
of  the  result  in  the  English  and  part  in  the  metric  system.  While 
the  latter  is  undoubtedly  the  more  scientific  and  desirable  one  for 
general  use,  it  is  not  in  commercial  vogue  in  this  country,  and  for 
this  reason  it  would  seem  wise  to  report  all  results  in  British  Ther- 
mal Units,  which  deal  with  pounds  of  water,  degrees  Fahrenheit, 
and  cubic  feet  of  gas,  all  of  them  standards  in  common  use  in  the 
business  life  of  the  United  States. 

There  is  much  to  be  said  against  the  Simmance-Abady  calorim- 
eter and  very  little  in  its  favor.  The  inlet  and  outlet  water  ther- 
mometers are  on  a  level  with  each  other  and  the  gas  flame  is  always 
visible,  and  these  are  very  desirable  features;  unfortunately,  they 
seem  to  be  almost  the  only  ones.  The  stand  on  which  the  instru- 
ment is  mounted  is  large,  heavy,  and  unwieldy,  and  tends  to  destroy 
the  usefulness  of  the  entire  apparatus,  if  portability  is  to  be  con- 
sidered. 

The  wooden  jacket  is  unsatisfactory;  it  is  provided  with  the  idea 
of  preventing  radiation,  but  if  water  be  spilled  upon  it,  as  frequently 
happens,  the  evaporation  causes  a  distinct  loss  of  heat  which  more 
than  offsets  the  possible  saving  of  radiant  heat.  Moreover,  this 
jacket  contains  many  joints  or  cracks,  and  is  therefore  difficult,  if 
not  impossible,  to  keep  clean. 

The  water  content  is  12  J  pounds,  or  over  eight  times  that  of  the 


OTHER   INSTRUMENTS    AND    METHODS  225 

Junker;  this  means  that  a  change  in  temperature  at  the  inlet  will 
require  a  comparatively  long  time  to  become  apparent  at  the 
outlet,  and  consequently  readings  covering  only  a  short  period  are 
extremely  liable  to  be  erroneous.  The  dial  of  the  meter  is  pur- 
posely so  divided  that  the  tests  may  be  made  with  fractional  revo- 
lutions of  the  drum;  this  tends  to  render  the  work  inaccurate. 
The  control  of  the  inlet  water  by  means  of  the  water  gauge  has  been 
found  to  be  extremely  unsatisfactory,  and  is  decidedly  inferior  to 
the  weir-overflow  method. 

The  Committee  of  the  American  Gas  Institute  in  its  report 
on  this  instrument  says:1  "The  circulation  of  water  through  the 
Simmance-Abady  calorimeter  does  not  seem  to  be  such  that  the 
heat  is  absorbed  from  the  waste  products  of  the  gas  with  any 
uniformity.  The  water  courses  up  and  down  through  the  instru- 
ment several  times  while  the  gases  go  through  once.  This  causes 
uneven  heating,  which  is  augmented  by  the  construction  of  the 
last  water  pocket  above  the  combustion  chamber.  This  arrange- 
ment made  the  outlet  water  temperature  very  difficult  to  control, 
and  led  us  to  believe  the  average  reading  of  the  outlet  thermometer 
did  not  record  the  average  temperature  of  the  outflowing  water." 

The  conclusions  of  this  committee  are  also  worthy  of  note: 
"  There  is  a  considerable  variation  in  the  results  obtained  on  the 
Simmance-Abady  instrument.  By  referring  to  the  original  record 
sheets  of  tests  made  on  the  Simmance-Abady  calorimeter,  we  find 
an  explanation  for  these  widely  varying  results.  Take  any  test 
at  random,  say  P-i;  the  temperature  of  the  outlet  water  varies 
from  85.75  to  86.70  degrees.  The  mercury  thread  in  the  outlet 
thermometer  was  never  steady  at  any  one  temperature  for  even  a 
few  seconds,  and  danced  up  and  down  over  a  considerable  distance, 
making  it  impossible  to  obtain  a  fair  average,  although  readings 
were  made  as  rapidly  as  they  could  be  recorded,  one  observing 
and  another  recording. 

"  Reference  to  the  comments  under  test  'L'  shows  that  with  the 
construction  of  this  Simmance-Abady  instrument  no  reliability  of 
result  was  obtained. 

1  Proceedings  American  Gas  Institute,  October,  1908. 


226  GAS   AND   GAS   METERS 

"  Comparison  of  results  in  Series  P,  between  the  Junker  and  the 
Simmance-Abady  instruments,  on  gas,  shows  the  Simmance-Abady 
about  10  per  cent  above  the  Junker. 

"  Owing  to  the  great  fluctuations  in  the  outlet  temperature  we 
are  not  at  all  certain  that  we  obtained  an  actual  average  of  the 
temperature  of  the  water  leaving  the  instrument.  However,  based 
on  the  two  series  of  tests,  one  with  the  electric  coil  heater  and  the 
other  on  gas,  both  showing  better  than  100  per  cent  efficiency,  we 
concluded  that  in  its  construction,  as  shown  in  this  instrument, 
which  is  about  five  years  old,  the  Simmance-Abady  instrument 
could  not  be  considered  satisfactory." 

It  should  be  added  that  the  electric  tests  mentioned  consisted  in 
supplying  electrically  a  known  quantity  of  heat  energy  for  a  known 
interval  of  time,  and  determining  the  quantity  of  heat  absorbed 
in  the  usual  way.  There  can  be  no  question  as  to  the  accuracy 
of  this  method,  and  since  it  gave  results  with  the  Junker  showing 
an  average  efficiency  of  that  instrument  of  99.5  per  cent,  it  is 
evident  that  the  Simmance-Abady  is  from  8  to  10  per  cent  in 
error,  and  is  therefore  not  to  be  recommended.  If,  however,  this 
instrument  is  desired,  it  may  be  procured  for  about  $110. 

NOTE.  Later  advice  from  Alexander  Wright  &  Co.  states  that  they  are  now 
prepared  to  furnish  this  instrument  with  a  polished  nickel  jacket  in  place  of  the 
wooden  one,  and  with  a  weir  overflow  similar  to  the  Junker.  This  removes  two 
of  the  most  serious  objections  to  the  instrument,  and  it  is  quite  possible,  though  not 
certain,  that,  with  these  changes,  the  calorimeter  may  give  perfect  satisfaction. 
The  cost  of  the  revised  instrument  complete  with  meter-governor  is  $169.50  deliv- 
ered in  New  York. 

The  Sargent  calorimeter  is  the  only  instrument  of  its  kind  which 
is  made  in  this  country  and  which  has  been  used  to  any  extent. 
It  is  seen  in  sectional  view  in  Fig.  35,  and  complete  with  accessories 
in  Fig.  36.  The  outer  casing  of  this  calorimeter  is  jacketed  with 
wood  to  prevent  radiation.  The  interior  is  a  combustion  chamber 
for  the  gas,  surrounded  by  a  compartment  containing  the  jacket 
water.  The  combustion  chamber  is  high  enough  to  allow  a 
suitable  flame  to  be  inserted  without  its  impinging  upon  any  part 
of  the  instrument. 


OTHER   INSTRUMENTS   AND   METHODS 


227 


IB 


Tipping  Bucket 


Fig.  35.     Sargent  Calorimeter. 
Sectional  View. 


°F   THE 

UNIVERSITY 


228  GAS   AND   GAS   METERS 

The  products  of  combustion  rise  to  the  upper  interior,  then  are 
diverted  down  through  a  series  of  small  tubes  to  the  bottom  and 
pass  on  out  through  an  opening,  the  size  of  which  is  controlled  by 
a  damper.  The  water  enters  in  an  opening  at  the  top  of  the 
calorimeter.  In  the  first  Sargent  instrument  the  water  passed 
down  through  and  just  inside  of  the  outer  shell,  then  up  and  down 
several  times,  surrounding  the  small  tubes,  carrying  off  the  pro- 
ducts of  combustion  of  the  gas,  and  finally  leaving  at  the  top  on  a 
level  with  the  inlet.  In  the  second  instrument  the  course  of  the 
water  was  down,  adjacent  to  the  outer  shell,  then  up  once,  surround- 
ing the  combustion  tubes,  and  passing  in  a  direction  opposite  to 
the  flow  of  the  products  of  combustion. 

The  water  head  was  originally  controlled  by  a  gauge  on  the  out- 
let, but  later,  a  fixed  elevated  weir  was  adopted  for  this  purpose. 

The  outflowing  water  also  leaves  the  calorimeter  through  a 
weir  overflow,  after  passing  through  a  controlling  cock.  The 
overflow  passes  to  an  automatic  dumping  bucket,  which  is  divided 
into  two  parts,  one  part  connecting  to  an  overflow  or  waste,  the 
other  passing  the  water  to  a  measuring  vessel.  This  dumping 
bucket  is  held  in  position  by  a  keeper.  The  weight  of  the  water 
in  the  full  side  tends  to  oscillate  the  bucket  so  that  the  water  will 
flow  into  the  empty  side  and  through  another  outlet  to  the  empty 
receptacle.  When  the  hand  of  the  gas  meter  passes  the  zero 
point  an  electrical  circuit  is  completed,  which,  passing  through 
the  solenoid,  draws  down  the  keeper,  and  allows  the  outlet  water 
to  automatically  change  from  the  full  to  the  empty  pail.  With 
such  a  device  the  personal  error  is  not  only  eliminated,  but  much 
of  the  work  of  the  operator  is  done  automatically,  thereby  allow- 
ing him  more  time  for  observing  the  temperatures  and  weighing 
the  water  delivered. 

The  gas  meter  is  of  the  wet  type,  with  a  drum  of  one-tenth  of  a 
cubic  foot  capacity  per  revolution.  The  dial  is  divided  in  thou- 
sandths of  a  cubic  foot. 

The  flow  of  gas  from  the  meter  to  the  burner  is  regulated  by  a 
small  leather  diaphragm  governor,  mounted  on  the  top  of  the 
meter,  at  the  gas  outlet. 


OTHER   INSTRUMENTS   AND   METHODS 


229 


The  thermometers  indicating  the  temperatures  of  both  inlet  and 
outlet  water  are  side  by  side,  on  the  same  level,  at  the  top  of  the 
calorimeter,  thus  enabling  both  to  be  easily  and  quickly  read. 
These  thermometers  read  in  the  Fahrenheit  scale,  and  are  sub- 
divided to  read  to  one-tenth  of  one  degree.  There  is  a  thermom- 
eter placed  near  the  outlet  damper  to  register  the  temperature  of 
the  outflow  products  of  combustion. 


Fig.  36.     Sargent  Calorimeter. 

The  water  after  passing  through  the  calorimeter  is  caught  in  a 
copper  vessel  and  weighed  on  platform  scales. 

By  weighing  the  discharged  water  and  using  Fahrenheit  ther- 
mometers no  transformation  of  units  is  necessary  to  get  the  result 
in  British  Thermal  Units. 

In  setting  up  the  calorimeter  the  meter  is  filled,  leveled,  and  the 
water  saturated  by  the  passage  of  gas  for  two  hours.  The  pres- 


230  GAS   AND   GAS   METERS 

sure  gauge  is  connected  to  the  top  of  the  glass  water  gauge,  and 
the  governor  to  the  outlet  on  the  top  of  the  meter.  The  battery 
is  coupled  with  the  terminals  on  the  front  and  top  of  the  meter 
and  with  the  solenoid.  The  water  supply  is  connected  to  the 
inlet,  and  a  rubber  tube  passed  from  the  inlet  and  outlet  overflows 
to  the  sink;  the  apparatus  is  then  ready  for  use. 

The  actual  test  is  carried  out  as  follows:  Regulate  the  flow  of 
water  so  that,  when  the  overflow  is  shifted  into  the  dumping 
bucket,  the  latter  shall  be  able  to  handle  the  stream  without 
danger  of  loss.  Rate  the  gas  at  5  feet  per  hour,  adjust  the  air 
mixer  so  that  the  tip  of  the  flame  barely  shows  a  luminous  point, 
and  place  the  burner  in  position  in  the  calorimeter.  Allow  the 
gas  to  burn  until  the  condensation  is  dripping  freely  and  regularly, 
and  the  temperature  of  the  outlet  water  is  constant.  Switch  the 
outlet  water  into  the  dumping  bucket,  a  weighed  copper  pail  being 
placed  under  each  spout.  Throw  the  switch  on  top  of  the  meter 
so  that,  as  the  meter  hand  passes  the  zero  mark,  the  circuit  is  com- 
pleted and  the  direction  of  the  outlet  water  changed  from  one 
copper  pail  to  the  other.  Make  as  many  readings  of  the  inlet 
and  outlet  water  thermometers  as  convenient,  and,  when  o.i  foot 
of  gas  has  been  burned  and  the  outlet  water  is  again  automatically 
shifted,  weigh  the  pail  containing  the  water  which  passed  during 
the  period  of  test.  Record  also  the  temperature  of  the  gas  in  the 
meter,  of  the  outlet  gas,  and  of  the  room,  and  the  barometric  read- 
ing. The  condensation  test  is  carried  out  exactly  as  with  the 
Junker  calorimeter  save  that  the  water  is  weighed  instead  of  being 
measured. 

Calculations.  Owing  to  the  fact  that  the  data  are  expressed 
entirely  in  English  units,  the  calculations  are  very  simple.  They 
may  be  expressed  by  the  usual  formula: 

W  X  T 

H  equals  • '—  when  H  equals  gross  British  Thermal  Units 

G 

per  cubic  foot  of  gas ;  W  equals  weight  of  water  in  pounds ;  T  equals 
difference  in  temperature  between  the  inlet  and  outlet  water,  in 
degrees  Fahrenheit;  and  G  equals  the  volume  of  gas  burned  cor- 
rected for  temperature  and  pressure. 


OTHER   INSTRUMENTS    AND    METHODS  231 

Example.  Gas  burned  (uncorrected)  o.i  cubic  foot.  Average 
temperature  of  inlet  water  62.1  degrees;  average  temperature  of 
outlet  water  83.5  degrees;  temperature  of  inlet  gas  63  degrees; 
temperature  of  outlet  gas  65  degrees;  temperature  of  room  63 
degrees;  barometer  29.50  inches;  weight  of  pail  plus  water  4.61 
pounds;  weight  of  pail  1.61  pounds;  weight  of  condensation  for 
one  cubic  foot  of  gas  0.06  pound.  Correction  for  barometer  1.7 
per  cent—  ;  for  temperature  0.8  per  cent—  ;  total  2.5  per  cent—. 

o.i  -j-  1.025  =  0.0976. 

4.61  pounds  —  1.61  pounds  =  3.00  pounds  of  water  passed. 

83.5  —  62.1  =  21.4  degrees  rise  in  temperature  of  the  water. 

Then 

H  =  3'°°  X  2I'4  =  658  gross  B.T.U.  per  cubic  foot. 
.0976 

For  the  heat  of  condensation,  multiply  the  weight  of  condensed 
water,  in  fractions  of  a  pound,  by  the  factor  1081,  and  divide  the 
product  by  the  corrected  volume  of  gas  burned.  Thus  in  the 
above  example: 

(.06  X  1081)  ^  0.976  =  66  B.T.U.  from  condensation. 

The  factor  1081  is  derived  in  the  following  manner:  the  latent 
heat  of  steam  is  537  calories,  and  this  amount  is  given  off  in  the 
transition  from  the  gaseous  to  the  liquid  state.  But  the  condensed 
water  does  not  leave  the  calorimeter  at  100°  C.,  but  more  nearly 
at  40  degrees,  and  therefore  gives  up  60  more  calories.  Therefore 
every  cubic  centimeter  of  condensation  collected  means  0.597 
calorie  to  be  deducted  from  the  gross,  to  get  the  net  result.  By 
multiplying  by  3.968  this  is  changed  to  British  Thermal  Units  per 
cubic  foot  per  cubic  centimeter  of  condensation;  and  since  one 
pound  equals  454  grams, 

0.597  X  3-968  X  454  =  1081  =  the  factor  to  be  used  in  multi- 
plying the  pounds  of  condensation  to  secure  the  British  Thermal 
Units  per  cubic  foot  loss  by  such  condensation. 

The  author  made  a  careful  investigation  of  the  Sargent  calorim- 
eter in  actual  operation,  discovering  many  good  features,  and 


232  GAS  AND   GAS   METERS 

some  very  poor  ones.  The  wooden  jacket  is  an  objection,  as 
was  shown  in  the  case  of  a  Simmance-Abady.  The  water  content 
is  1 2  pounds,  an  amount  too  large  for  general  and  rapid  use,  since 
slight  changes  in  the  heating  value  of  the  gas  are  liable  to  pass 
unnoticed.  The  legs  are  not  adjustable,  thus  complicating  the 
process  of  leveling  the  calorimeter.  The  governor  did  not  work 
satisfactorily,  and  it  is  believed  that  a  wet  governor,  of  the  type 
used  with  the  Junker  calorimeter,  should  be  substituted. 

The  meter  furnished  with  the  instrument  occasioned  con- 
siderable trouble.  There  is  only  one  hand  on  the  dial,  so  that 
when  it  is  desired  to  pass  one  foot  of  gas  to  obtain  the  condensa- 
tion, the  operator  must  either  count  the  revolutions,  or  establish 
the  rate  accurately  and  remove  the  graduate  from  the  condensate 
outlet  after  the  lapse  of  a  given  time.  The  height  of  the  water 
in  the  gauge  glass  is  determined  by  a  pin  which  projects  down- 
ward from  the  top;  this  was  found  to  be  much  more  difficult  to 
read  accurately  than  the  ring  or  scratch  usually  placed  on  the 
outside  of  the  glass.  Several  times  in  adjusting  the  water  line 
the  latter  stuck  badly,  due  to  the  stoppage  of  the  minute  orifice 
in  the  top  of  the  gauge.  The  meter  is  provided  with  a  single 
circular  level;  two  rectangular  ones  at  right  angles  to  each  other 
would  be  better. 

The  metallic  strip  which  completes  the  electrical  circuit  when 
the  meter  hand  reaches  the  zero  mark  must  be  very  carefully 
adjusted,  or  it  will  either  entirely  stop  the  hand,  or  will  not  make 
close  contact  enough  to  release  the  keeper.  The  system  became 
short-circuited  several  times  through  the  spilling  of  water  from 
the  bucket,  and  after  five  or  six  experiments  had  been  lost  in  this 
way,  the  battery  was  disconnected  and  the  keeper  released  by 
hand.  This  worked  fairly  well,  but  does  away  with  some  of  the 
advantages  claimed  for  the  instrument,  i.e.  the  elimination  of 
the  personal  element  and  the  automatic  performance  of  much  of 
the  operation. 

The  burner  has  no  cock  for  the  adjustment  of  the  flow  of  gas, 
a  rather  serious  defect.  With  the  instrument  tested,  the  air 
mixer  was  so  loose  that  it  would  not  stay  in  position,  and  the 


OTHER   INSTRUMENTS   AND   METHODS  233 

greatest  care  had  to  be  exercised  to  prevent  its  moving  after  hav- 
ing been  once  adjusted. 

The  lower  part  of  the  body  of  the  calorimeter  was  so  near  the 
table  that  considerable  difficulty  was  experienced  in  inserting 
the  burner.  This  was  the  more  noticeable  since  the  writer  never 
had  any  trouble  with  the  Junker  in  this  respect,  although  this  is 
one  of  the  points  that  was  raised  against  the  latter  instrument  by 
the  Committee  of  the  American  Gas  Institute. 

The  spout  from  which  the  condensed  water  drips  is  so  low  that 
a  25  c.c.  graduate  cannot  be  placed  under  it;  the  water  must 
therefore  either  be  weighed  or  turned  from  one  vessel  to  another 
to  be  measured.  As  the  total  condensate  from  one  cubic  foot  of 
gas  is  rarely  over  30  c.c.,  or  about  one-fifteenth  of  a  pound,  and  the 
balance  furnished  weighs  only  to  o.oi  pound,  there  is  liable  to  be 
an  error  of  as  much  as  14  per  cent  in  determining  the  weight  of 
the  condensate. 

The  damper  for  the  outlet  gases  consists  simply  of  a  tin  slide, 
which  cannot  be  fixed  in  any  one  position  (unless  the  outlet  be 
wide  open  or  totally  closed)  without  the  application  of  external 
aid. 

The  thermometers  for  the  inlet  and  outlet  water  are  entirely 
too  large  in  diameter,  and  the  divisions  very  fine.  Reflections 
from  all  sides  made  it  almost  impossible  to  read  them  accurately, 
even  to  tenths  of  a  degree.  A  reading  lens  proved  of  material 
assistance,  and  should  always  be  used. 

The  dumping  bucket  caused  considerable  trouble,  and  several 
times  shifted  when  it  should  not  have  done  so. 

To  offset  these  disadvantages  it  must  be  admitted  that  when 
everything  was  running  properly  one  man  could  handle  the  instru- 
ment with  ease  and  accuracy.  The  thermometers  are  on  the 
same  level,  a  most  desirable  feature.  The  weighing  of  the  water 
worked  splendidly,  and  the  personal  equation,  which  enters  when 
the  outlet  is  shifted  from  one  receptacle  to  another,  was  entirely 
eliminated.  A  long  series  of  tests  was  made  to  show  the  accu- 
racy of  the  instrument  at  differing  rates  of  water  and  gas,  and 
with  varied  regulation  of  the  air  supply  to  the  burner.  A  check 


234  GAS    AND    GAS    METERS 

series  was  run  with  the  Junker  calorimeter,  using  the  same  gas 
supply.  The  results  are  given  in  a  table  in  the  appendix,  and 
show  (i)  that  the  efficiency  of  the  Sargent  calorimeter  is  only 
about  98  per  cent  as  compared  with  99.5  per  cent  for  the  Junker; 
(2)  that  the  efficiency  was  nearly  the  same  for  all  rates  of  gas 
from  4  to  7  cubic  feet  per  hour;  (3)  that  a  slight  mistake  in  the 
regulation  of  the  air  mixer  does  not  alter  the  results  within  the 
limits  of  error  of  the  process;  (5)  although  this  does  not  appear 
from  the  above  figures,  it  was  shown  that  a  slight  change  in  the 
rate  of  flow  of  the  water  between  two  tests  made  no  difference  in 
the  results,  provided  that  sufficient  water  was  used,  and  that, 
when  the  valve  to  the  bucket  was  open,  no  water  was  escaping  by 
the  outlet  overflow. 

In  conclusion,  it  is  the  writer's  opinion  that  the  Sargent  calorime- 
ter, with  a  few  changes  as  suggested,  is  an  excellent  instrument;  it 
is  too  heavy  for  portable  work,  weighing  with  all  accessories  about 
80  pounds;  its  efficiency  has  only  been  tested  with  water  gas;  but  if 
it  is  compared  with  a  Junker  for  the  kind  of  gas  to  be  tested,,  its 
per  cent  of  efficiency  determined  and  this  figure  used  in  all  calcula- 
tions, it  would  seem  to  be  a  very  satisfactory  piece  of  apparatus. 
Its  cost,  however,  is  considerable,  and  is  composed  of  the  following 
items,  as  taken  from  the  descriptive  pamphlet  of  the  manufacturers.: 
Calorimeter  complete  with  automatic  discharge  buckets,  ther- 
mometers, tubing,  beaker  and  Bunsen  burner,  $150;  gas  pressure 
regulator  with  micrometer  adjustment  and  ordinary  U-tube  pres- 
sure gauge,  $20;  special  wet  test  meter  with  electrical  attachment, 
batteries  and  wire,  $70;  two  balanced  copper  receiving  pails  in 
which  water  is  weighed,  $3;  special  ten-pound  scales  weighing  to 
.01  pound  for  accurate  work,  $10;  two  reading-glasses  for  ther- 
mometers, $2;  total,  $255,  as  compared  with  $225  for  the  Junker. 

If  the  latter  instrument  be  so  altered  that  the  thermometers  are 
on  a  level,  it  is  unhesitatingly  recommended  as  by  far  the  most 
accurate  and  satisfactory  calorimeter  for  all  purposes. 

Later  advice  from  the  manufacturers  of  this  instrument  shows 
that  they  have  appreciated  the  nature  of  the  defects,  and  have 
remedied  some  of  them.  They  will  now  furnish  a  calorimeter 


OTHER   INSTRUMENTS   AND    METHODS  235 

with  a  nickel  jacket,  a  cock  will  be  placed  on  the  burner,  leveling 
screws  on  the  legs,  and  a  mark  on  the  outside  of  the  water  gauge 
for  adjusting  the  meter.  The  inlet  tube  is  to  have  a  valve  with  a 
quadrant  arm;  the  water  content  is  to  be  diminished  and  a  better 
thermometer  is  to  be  supplied. 

With  these  and  other  improvements  which  will  be  made,  the 
Sargent  calorimeter  will  be  found  to  furnish  an  extremely  satisfac- 
tory instrument  for  permanent  installations.  Indeed,  in  some 
respects  it  is  superior  to  the  Junker,  and  should  its  efficiency  under 
the  new  conditions  prove  equal  to  that  of  the  latter  instrument,  it 
may  replace  the  latter  as  a  standard  apparatus.  It  is  only  fair  to 
state  that  the  writer  is  informed  by  the  manufacturers  that  the  effi- 
ciency, as  secured  by  the  committee  of  the  American  Gas  Institute, 
was  found  to  be  99.4  per  cent. 

The  latest  instrument  in  the  field  is  a  portable  one  placed  on  the 
market  late  in  1908.  It  is  called  the  Simmance-Abady  Portable 
Calorimeter,  and  the  following  description  is  given  by  the  manu- 
facturers: "The  instrument  is  very  simple,  strictly  portable,  of 
guaranteed  accuracy  and  very  cheap,  and  the  following  brief 
description  will  explain  its  working:  The  Simmance-Abady  Port- 
able Calorimeter  consists  of  two  parts,  A,  the  combined  gas 
aspirator  and  measure;  B,  the  calorimeter  vessel  (Fig.  37).  The 
aspirator  is  quite  light  and  can  be  carried  in  one  hand,  and  the 
charge  of  gas  drawn  into  it  even  against  a  high  vacuum.  The 
outlet  pipe  is  slipped  on  to  the  burner  of  the  calorimeter,  which  has 
previously  been  filled  with  one  liter  of  water  and  the  temperature 
noted. 

"The  burner  is  lighted  and  a  definite  quantity  of  the  collected 
gas  is  automatically  measured  and  burned,  the  heat  being  imparted 
to  the  water.  The  difference  in  the  thermometer  readings  before 
and  after  test  is  multiplied  by  the  water  value  of  the  instrument, 
and  the  result  is  standard  British  Thermal  Units  per  cubic  foot." 

The  water  value  referred  to  is  obtained  by  standardization  with 
gas  of  known  heating  value.  The  makers  believe  that  with  careful 
manipulation  the  instrument  is  as  accurate  as  the  Junker;  but  this 
claim  remains  to  be  proved.  The  total  weight  of  the  apparatus  is 


GAS  AND  GAS  METERS 

25  pounds;  its  cost  in  this  country  is  $80,  and  it  can  be  packed  in  a 
box  of  inside  dimensions  of  18  X  10  X  24  inches.  If  the  claims  in 
its  favor  should  be  substantiated,  a  valuable  portable  calorimeter 
has  been  evolved;  but  until  such  verification  has  been  made,  the 
instrument  should  be  employed  with  caution. 


Fig-  37-     Simmance-Abady  Portable  Calorimeter. 

Very  recently  there  has  been  a  considerable  number  of  calo- 
rimeters of  new  design  described  in  various  technical  journals, 
and  some  of  these  are  already  upon  the  market.  The  Committee 
of  the  American  Gas  Institute  did  not  investigate  these  instruments. 
The  reasons  given  for  such  omission  are  excellent  and  are  best  given 
in  the  words  of  their  report:  "The  only  calorimeters  considered  by 
your  Committee  were  of  the  Junker  or  water  heater  type,  measuring 


OTHER   INSTRUMENTS   AND    METHODS  237 

the  gas  and  determining  the  calorific  power  by  transferring  the  heat 
developed  to  a  known  quantity  of  water,  and  determining  the  rise 
in  temperature  of  this  water. 

"  This,  we  think,  is  the  only  practical  type  of  calorimeter  on  the 
market,  and  at  this  writing  your  Committee  disapproved  of  the 
adoption  for  commercial  practice  of  any  instrument  which  deter- 
mines the  heating  value  by  raising  the  temperature  of  metals,  or 
that  records  the  heating  value  by  measuring  the  density  of  liquids, 
or  by  which  the  heating  value  is  deduced  from  the  quantity  of  air 
required  for  combustion. 

"We  also  disapprove  of  the  use  of  calorimeters  which  do  not 
measure  the  total  heating  value  of  the  gas.  There  have  been 
designed  calorimeters  that  allow  the  products  of  combustion  to 
leave  at  temperatures  such  that  the  water  vapors  formed  in  the 
process  of  combustion  will  not  be  condensed  in  the  instrument. 
This  method  of  operating  a  calorimeter  allows  for  many  chances  of 
error,  and  it  does  not  provide  for  measuring  the  sensible  heat  that 
is  lost  in  these  products  of  combustion,  and  also  increases  the  error 
occasioned  by  the  presence  of  moisture  in  the  atmosphere." 

While  such  calorimeters  have  yet  to  prove  their  value,  it  is  not 
impossible  that  the  future  may  see  one  of  them  superseding  the 
Junker  and  similar  instruments,  and  a  short  description  will  there- 
fore be  given  of  several  of  them,  each  embodying  a  different 
principle. 

In  the  Journal  fur  Gasbeleuchtung,  49,  1056,  M.  Casaubon  gives 
a  new  method  for  the  determination  of  heat  units  in  gas.  He 
states  that  the  calorific  value  of  a  gas  mixture  is  equal  to  the  sum 
of  the  calorific  values  of  the  different  constituents.  Practically, 
it  is  possible  to  determine  the  heating  value  of  a  lighting  gas  by 
determination  of  the  air  volume  necessary  for  the  complete  com- 
bustion. M.  Casaubon  uses,  as  a  medium  for  the  determination 
of  the  complete  combustion,  a  radiant  mantle  of  cerium  oxide,  to 
which  the  air  is  brought  through  a  gas  meter.  The  point  where 
the  reducing  flame  goes  over  to  the  oxidizing  flame  is  marked  very 
sharply  by  a  change  of  the  color  from  red  to  white.  A  minimum 
change  in  the  addition  of  the  air  caused  a  sudden  and  distinct 


238  GAS  AND   GAS  METERS 

change  in  the  color.  The  radiant  mantle  is  obtained  by  soaking 
an  ordinary  mantle  in  a  30  per  cent  solution  of  cerium  nitrate. 
The  dial  of  the  gas  clock  is  divided  directly  in  calories. 

A  determination  of  the  heating  value  of  the  lighting  gas  needs 
three  or  four  minutes,  and  the  mistakes  caused  by  reading  are 
said  not  to  exceed  three  or  four  calories.  The  calorimeter  is 
also  capable  of  employment  with  gases  other  than  illuminating 
gas. 

Mr.  F.  C.  Jones,  in  the  American  Gas  Light  Journal  for  Novem- 
ber 4,  1907,  proposes  the  following:  Each  combustible  gas  has  its 
own  definite  number  of  thermal  units,  depending  upon  and  as 
unchangeable  as  its  chemical  formula;  it  also  requires  a  certain 
definite  volume  of  air  for  complete  combustion.  A  study  of  the 
relation  of  the  thermal  value  to  the  air  required  reveals  the  fact, 
or  law,  that  equal  volumes  of  all  perfectly  combustible  mixtures  of 
air  and  gas  contain  the  same  number  of  thermal  units.  Thus,  one 
cubic  foot  of  hydrogen  contains  344  B.T.U.  and  requires  2j  cubic 
feet  of  air  for  complete  combustion;  i  cubic  foot  methane  -equals 
1073  B.T.U.  and  requires  10  cubic  feet,  of  air.  Then  3^  cubic  feet 
of  the  mixture  of  air  and  hydrogen  equals  344  B.T.U.  and  n  cubic 


feet  of  air  and  CH4  (methane)  equals  1073  B.T.U.  —7  or 

equals  nearly  100.  Therefore  one  unit  gas  and  the  number  units 
of  air  required  for  complete  combustion,  multiplied  by  100,  equals 
British  Thermal  Units  per  cubic  foot  of  gas. 

There  are  cases  where  this  does  not  hold  good,  but  this  may  be 
due  to  the  factor's  not  being  exactly  correct.  To  use  this  principle 
in  determining  the  calorific  value  of  a  gas,  take  10  c.c.  of  the  sample 
and  explode  it  with  an  excess  of  air,  say  70  c.c.,  and  determine 
the  amount  of  such  excess,  which  may  be  assumed  to  be  10  c.c. 
Now  10  c.c.  of  gas  required  60  c.c.  of  air  for  complete  combustion; 
then  i  cubic  foot  of  gas  would  use  6  cubic  feet  of  air,  making  a 
total  of  7  cubic  feet,  each  of  which  contains  the  thermal  constant 
100.  Therefore  the  heating  value  of  the  gas  in  B.T.U.  per  cubic 
foot  would  be  7  times  100,  or  700.  Mr.  Jones  states  that  practice 
has  confirmed  the  correctness  of  such  procedure,  although  if  the 


OTHER  INSTRUMENTS   AND   METHODS  239 

B.T.U.  are  less  than  100,  as  with  a  lean  producer  gas,  the  law  does 
not  apply. 

In  the  Journal  of  Gas  Lighting  for  July  30,  1907,  is  described 
the  Beasley  calorimeter.  This  instrument  is  not  intended  to 
record  gross  heating  values,  but  rather  the  amount  of  heat  available 
for  practical  purposes.  It  consists  of  a  U-tube  rilled  with  oil  from 
a  reservoir,  one  limb  of  the  tube  being  heated  by  the  gas  to  be 
tested,  while  the  other  is  kept  cool.  The  difference  in  height  of 
the  oil  columns  is  considered  to  be  a  measure  of  the  calorific  value 
of  the  gas.  By  suitable  floats,  clockwork,  and  so  forth,  the  record 
may  be  transcribed  on  a  paper  diagram,  and  thus  a  continuous 
record  may  be  kept.  A  pressure  regulator,  stream  controller  and 
special  atmospheric  burner  are  used. 

The  Fery  calorimeter  depends  on  the  difference  in  potential 
produced  in  a  thermo-electric  couple,  one  junction  of  which  is 
heated  by  the  gas  to  be  tested.  The  apparatus  is  standardized 
by  means  of  a  standard  amyl  acetate  lamp.  The  products  of 
combustion  rise  through  a  glass  chimney,  the  top  of  which  is 
covered  with  a  perforated  nickel  plate  carrying  one  junction  of  a 
copper-constantin  thermo-electric  couple.  The  other  junction  is 
similarly  placed  at  the  top  of  the  second  chimney,  down  which  the 
cold  air  for  the  combustion  is  drawn,  a  metallic  tube  forming  the 
connection  between  the  lower  ends  of  the  two  chimneys.  The 
first  junction  is  heated  by  the  products  of  combustion  to  a  tem- 
perature of  nearly  400  degrees,  giving  a  difference  of  potential  of 
about  1 6  millivolts  between  the  two  junctions.  Experiment  has 
shown  that  the  voltage  thus  obtained  is  very  exactly  proportional 
to  the  calorific  power  and  to  the  weight  of  fuel  burned  in  a  unit 
of  time.  The  apparatus  can  be  made  self-registering  by  use  of  an 
integrating  wattmeter  whose  velocity  is  proportional  to  the  voltage 
of  the  thermo-electric  couple.  The  instrument  is  seen  in  Fig.  38. l 

Raupp's  gas  calorimeter  is  described  by  Lux  as  being  superior 
to  the  Junker.  It  consists  chiefly  of  a  copper  cylinder  whose  lower 
part  is  solid,  the  hollow  upper  part  carrying  a  thermometer  divided 
into  tenths.  Under  the  copper  body  is  placed  at  a  certain  time  the 

1  Journal  Gas  Lighting,  June  18,  1907,  p.  817. 


240 


GAS   AND    GAS   METERS 


gas  flame,  whose  height  has  been  previously  determined,  and  the 
time  necessary  for  the  thermometer  to  rise  10  degrees  is  noted. 
The  apparatus  is  standardized  by  means  of  gases  of  known  heating 
value,  so  from  the  measured  time  the  heating  value  can  be  calcu- 
lated by  consulting  a  table  prepared  for  that  purpose. 


Fig.  38.     Fery  Calorimeter. 

Schonberger's  method  is  based  on  the  fact  that  the  speed  of  con- 
flagration of  a  gas  is  in  determinate  proportion  to  its  calorific 
value,  and  also  depends  on  its  pressure.  The  apparatus  consists 
of  a  burner  and  a  regulating  valve,  which  controls  the  inflow  of 
gas  from  the  source  of  supply  into  a  receiver,  to  which  is  attached 
a  manometer  tube.  The  height  of  the  flame  and  the  gas  pressure 
are  read  off  on  graduated  scales  attached  to  the  burner  and  tube, 
the  pressure  being  regulated  by  the  valve  until  the  flame  is  on  the 
point  of  extinction.  This  instrument  has  been  recently  patented 
in  France,  but  has  probably  never  been  tested  save  by  its  inventor. 

The  essential  parts  of  Stoecker  and  Rothenbach's  calorimeter 
are  an  upright  glass  tube,  2.5  cm.  in  diameter,  expanded  in  the 
middle  into  a  bulb.  The  upper  part  of  the  tube  is  contracted  to  a 
diameter  of  8  mm.  and  bent  at  right  angles.  The  lower  end  of 
the  tube  is  also  narrowed  somewhat  in  diameter,  bent  at  right 
angles,  graduated  into  divisions  representing  o.i  c.c.  and  employed 
to  form  one  of  the  feet  of  the  instrument. 


OTHER   INSTRUMENTS   AND   METHODS  241 

At  a  height  of  5  cm.  above  the  base,  the  coiled  condensing  tube 
is  sealed  into  the  above  mentioned  tube.  The  condenser  is  2.5 
meters  long,  and  8  to  10  mm.  in  diameter.  A  lateral  neck  is  fused 
into  the  side  of  the  bulb  of  the  main  tube  about  one-half  way  up, 
into  which  a  brass  sleeve  is  accurately  ground.  This  carries  the 
system  of  tubes  through  which  the  gas  burned  in  the  calorimeter, 
and  the  wires  conveying  a  current  of  electricity  for  its  ignition,  are 
passed.  These  three  tubes  are  fixed  into  the  brass  sleeve  by  means 
of  a  putty  composed  of  litharge  and  pure  anhydrous  glycerine. 

The  whole  piece  of  glass  apparatus  is  placed  in  a  vessel  con- 
taining water,  constructed  in  the  manner  designed  by  Mahler,  the 
quantity  of  water  being  so  calculated  that  it  rises  in  temperature 
by  one  degree  for  every  4500  large  calories  absorbed.  The  calo- 
rimeter is  intended  as  a  convenient  instrument  for  rapid  estimation 
of  the  heating  power  of  small  volumes  of  gas;  it  requires,  however, 
two  men  to  operate  it.1 

Graefe's  calorimeter  is  seen  in  Fig.  39,*  and  is  composed  of  the 
following  parts:  a  thermometer,  T;  a  stirrer,  R;  a  vessel,  M, 
which  holds  5  liters,  for  measuring  the  gas;  a  pipe,  A,  for  filling 
M  with  water;  a  regulator,  A7",  which  automatically  sets  the  level 
of  the  liquid;  a  pipe,  C,  leading  to  the  sink;  and  a  pipe,  E,  which 
can  be  attached  either  to  the  tube  delivering  gas  or  to  the  burner, 
B.  The  operation  in  brief  is  as  follows:  When  the  bottle  is  com- 
pletely full  of  gas,  E  is  connected  to  the  burner,  the  gas  is  lighted, 
and  D  is  so  regulated  that  the  flame  is  constantly  two  to  three 
centimeters  high.  While  gas  flows  out  of  M,  water  is  admitted 
through  A  at  such  speed  that  some  regularly  overflows  through 
U\  this  keeps  the  pressure  constant.  During  the  combustion  of 
gas  the  stirrer,  R,  is  worked  in  the  usual  manner,  and  finally  the 
highest  point  to  which  the  mercury  rises  in  the  thermometer  above 
that  which  was  indicated  at  the  beginning  of  the  test  is  read  off. 

While  not  at  all  in  the  class  with  any  of  the  above,  a  short  descrip- 
tion must  be  given  of  the  automatic  Junker  calorimeter.  This 
instrument  is  similar  to  the  ordinary  form  of  Junker,  the  heat  of 

1  Journal  Gas  Lighting,  April  14,  1908. 

2  Journal  Gas  Lighting,  Oct.  8,  1907. 


242 


GAS  AND   GAS   METERS 


the  flame  being  transmitted  to  a  stream  of  water.  The  value  is 
calculated  from  the  quantities  of  water  and  gas,  and  the  rise  in 
temperature  of  the  water.  In  the  automatic  calorimeter  the  flow 
of  water  and  gas  is  constant,  the  difference  in  the  temperature 
giving  a  direct  indication  of  the  calorific  value.  The  instrument 
consists  of  the  calorimeter  proper,  an  automatic  gas  pressure 
regulator,  an  automatic  water  regulator,  gas  meter  and  a  thermo- 


Fig-  39.     Graefe  Calorimeter. 

couple  connected  to  a  millivolt  meter.  A  recording  device  is 
also  furnished  whereby  a  continuous  record  of  heating  values  may 
be  kept.  The  complete  apparatus  can  be  purchased  for  about 
$800. 

It  is  the  custom  in  many  places  to  calculate  <he  heating  value 
from  an  analysis  of  the  gas.  The  results  obtained  in.  this  way 
may  or  may  not  be  reliable,  for  the  reason  that  it  is  almost  impos- 
sible to  exactly  determine  the  per  cent  of  the  various  hydrocarbons 


OTHER   INSTRUMENTS   AND    METHODS 


243 


in  the  gas,  and  such  determination  is  rarely  made  in  a  gasworks 
analysis.  This  introduces  a  serious  error,  because  of  the  fact  that 
the  hydrocarbons  are  among  the  important  heating  elements  in 
the  gas,  and  the  variation  in  their  calorific  value  may  be  seen 
from  the  following  table:1 


Name. 

Symbol. 

Volume    air   re- 
quired for  each 
volume. 

B.T.U.  gross  per 
cu.  ft.  at  60° 
and  30". 

Hydrogen 

H 

2    38 

^26    2 

Carbon  monoxide  . 

CO 

*•   3^ 

2.  38 

32  1     C 

Methane  

CH4 

0.  ^2 

»        6^6-  3 
IOOO    O 

Ethane  

C2Hfi 

16.  66 

1764.   4 

Propane  

C,H8 

2?.  8 

2521  o 

Butane  

3O.  Q4 

•3274.  o 

Ethylene 

CoH, 

14    28 

1588  o 

Propylene  .  .  . 

C3H6 

21    4.2 

2747    2 

Butylene  

C4HS 

28.^6 

•2OQQ    2 

Acetylene.  

II.  QO 

14.76   7 

Allylene 

C  H 

IQ    O4 

Benzene 

C*H0 

•2  r    70 

•"DO-  w 

^8o7    4 

To  calculate  the  heating  value  from  an  analysis,  first  obtain  the 
calorific  values  of  the  combustible  constituents;  these  are  worked 
out  per  cubic  foot.  Then  multiply  the  per  cent  of  each  constituent 
by  its  corresponding  calorific  value,  add  the  products  and  divide 
by  100,  and  the  result  will  be  the  calorific  value  of  the  gas  per 
cubic  foot. 


Example. 
A  =  1.0%; 


H 


CO  =  5.9%. 


CH4  =  34.2%; 


54.1  X     326  =  17,637 

34.2  X  1009  =  34,5°8 
3.0  X  1588  =     4,764 
i.o  X  3807  =    3,807 
5.9  X    323  =     1,906 


Total          62,622 
62,622  -f-  loo  =  626.2  B.T.U.  per  cubic  foot. 

1  Abady's  Gas  Analysis  Manual. 


CHAPTER  III. 
CONSIDERATION  OF  RESULTS. 

THE  results  of  a  heat  unit  test  will  naturally  vary  according 
to  the  nature  of  the  gas  which  is  being  examined;  it  may  be  of 
interest,  however,  to  state  the  values  found  in  various  places  and 
for  different  kinds  of  gas.  In  Magdeburg,  Germany,  the  aver- 
age gross  British  Thermal  Units  for  the  year  1907  was,  for  coal 
gas,  550;  for  water  gas,  487;  and  for  mixed  gas,  534.  The 
candlepower  of  these  gases  is  not  given,  but  must  in  every  case 
have  been  low.  In  Zurich,  the  average  net  calorific  value  of  the 
gas  manufactured  during  1907  was  552  British  Thermal  Units  per 
cubic  foot  at  60  degrees  and  30  inches  pressure,  calculated  for 
gas  in  the  dry  state;  its  illuminating  power  when  burned  in  a  slit 
burner  at  a  rate  of  5.3  cubic  feet  per  hour  averaged  10  candle- 
power.  Coal  gas  of  600  British  Thermal  Units  and  17  candle- 
power  is  furnished  in  Sheffield,  England,  according  to  figures 
quoted  in  the  Journal  of  the  American  Chemical  Society  Abstracts, 
January  20,  1907.  In  Liverpool  the  average  of  263  tests  made 
during  1907  was  668.91  British  Thermal  Units  net,  and  the  cor- 
responding candlepower  was  20.7.  The  Colombo  Gas  and  Water 
Company  of  Colombo,  South  America,  has  a  contract  with  the 
municipality  for  lighting  the  city  with  gas  of  10  candlepower 
and  400  British  Thermal  Units. 

In  America  the  heating  value  is,  as  a  rule,  much  higher  than 
abroad.  During  the  winter  months  of  1906  the  Inspector  for 
the  District  of  Columbia  found,  as  the  average  of  8  tests,  that  the 
British  Thermal  Units  in  Washington  gas,  which  is  a  mixed  gas  of 
about  22  to  23  candlepower,  was  632.3,  with  a  minimum  of  593.3 
and  a  maximum  of  651.1.  The  Massachusetts  State  Inspec- 
tor's Report  for  January,  1902,  shows  that  in  seven  cities,  the 
calorific  value  of  the  gas  varied  from  708  to  594  British  Thermal 

244 


CONSIDERATION   OF  RESULTS 


245 


Units,  the  average  being  655.  In  New  York  State  a  long  series 
of  tests  was  made  in  1908,  and  the  results  will  be  given  in  full  in 
the  discussion  on  the  relation  of  candlepower  and  heat  units. 

The  generally  accepted  theory  is  that  a  good  coal  gas  of  16 
candlepower  should  have  from  600  to  625  gross  British  Thermal 
Units  per  cubic  foot,  and  a  carburetted  water  gas  of  20  candle- 
power  will  have  a  slightly  greater  amount.  Considering  equal 
candlepowers,  there  is  no  question  as  to  the  superiority  of  the 
coal  gas  in  heating  value.  In  the  Journal  of  Gas  Lighting,  Jan- 
uary 14,  1908,  appears  an  article  on  coke  oven  gas,  in  which  the 
following  figures  are  given: 


Coke  oven  gas. 

Retort  coal  gas. 

Carburetted 
water  gas. 

British    Thermal    Units    per 
cubic  foot  
Candlepower  

730 
17-5 

669 

15-5 

719 

20.7 

These  figures  may  be  true  for  some  isolated  case,  but  the  heat- 
ing values  are  far  higher,  considering  the  illuminating  power, 
than  the  writer,  in  a  rather  wide  experience  with  gases  of  all 
candlepowers,  has  ever  found. 

O'Connor  gives  the  calorific  value  of  coal  gas  as  600  to  625 
British  Thermal  Units,  and  of  carburetted  water  gas  as  700,  and 
these  figures  seem  much  nearer  the  truth,  although  even  700  is 
rather  higher  than  the  usual  B.T.U.  found  in  water  gas  at  the 
present  time. 

With  natural  gas  it  is  clearly  impossible  to  state  any  heating 
value  which  shall  be  of  wide  application,  owing  to  the  differences 
in  composition  of  gases  from  various  fields.  The  Metric  Metal 
Company  in  its  catalogue  gives  the  figures  for  natural  gas  as  fol- 
lows: average  of  Pennsylvania  and  West  Virginia  fields,  1145 
B.T.U. ;  of  Ohio  and  Indiana,  1095;  of  Kansas,  noo.  The 
writer  made  an  investigation  of  the  gas  from  northwestern  Penn- 
sylvania and  found  heat  units  ranging  from  1190  to  1352.  Gill, 
in  his  "  Gas  and  Fuel  Analysis,"  states  the  calorific  value  of  natural 


246  GAS   AND   GAS   METERS 

gas  to  be  980  B.T.U.  per  cubic  foot;  it  is  therefore  probable  that 
the  correct  figures  are  about  1000  to  1200.  It  should  be  stated 
that  the  heat  of  condensation  with  natural  gas  is  much  greater 
than  with  coal  or  water  gas,  the  Jamestown  samples  mentioned 
having  from  88  to  118  B.T.U.  in  this  form. 

Oil  gas  is  very  rich  in  calorific  constituents,  and  the  B.T.U.  may 
reach  as  high  a  figure  as  1400.  Acetylene  is  also  a  valuable  gas 
for  heating  purposes,  and  while  there  are  very  few  results  pub- 
lished regarding  the  commercial  gas,  the  theoretical  heat  value 
of  pure  acetylene  gas  is  1477  B.T.U.  per  cubic  foot  (gross),  and 
there  is  little  reason  to  doubt  that  in  present  practice  this  figure 
will  be  closely  approximated. 

Standards.  Standards  for  the  heating  power  of  gas  have  been 
established  in  many  places,  and  it  is  hoped  and  expected  that 
others  will  soon  follow  their  lead.  In  Germany  there  is  no  gen- 
erally accepted  standard  of  calorific  value,  but  the  gas  is  care- 
fully tested  in  this  respect,  and  the  figures  from  a  number  of 
cities  show  that  on  an  average  the  gas  contains  532  to  585  gross 
B.T.U.  per  cubic  foot.  In  Colombo,  as  has  been  stated,  the 
standard  is  400  B.T.U.;  in  Omaha,  Nebraska,  600;  in  Dallas, 
Texas,  650;  in  Milwaukee,  Wisconsin,  600  (established  by  Dr. 
David  Fisher,  chemist  for  the  state  of  Wisconsin");  and  the  Wis- 
consin Railroad  Commission  has  set  the  standard  for  the  entire 
state  as  600  for  a  monthly  average,  with  a  minimum  of  550. 
These  few  instances  will  show  the  trend  of  opinion  in  scientific 
and  government  circles  to-day. 

The  Relation  of  Calorific  Value  to  Candlepower  and  Flame 
Temperature.  A  great  deal  has  been  written  on  this  subject,  and 
it  is  not  proposed  to  enter  into  a  detailed  discussion  of  the  ques- 
tion here,  but  merely  to  gather  together  some  of  the  facts  and 
figures  which  have  resulted  from  investigations.  The  opinions 
of  different  experimenters  vary  widely,  and  the  writer  does  not 
pretend  to  guarantee  the  accuracy  of  any  of  them;  indeed,  it  is 
his  personal  belief  that  there  is  no  definite  relation  between 
candlepower  and  calorific  power,  and  this  for  the  reason  that  the 
two  depend  upon  entirely  distinct  factors  connected  w;th  the 


CONSIDERATION    OF  RESULTS  247 

constitution  of  the  gas,  and  a  change  in  composition  which  will 
greatly  alter  the  heat  units  will  have  little  or  no  effect  on  the 
candlepower.  To  understand  this  it  is  only  necessary  to  con- 
sider the  gases  methane  and  hydrogen  with  heating  values  of 
1009  and  326  B.T.U.  respectively,  and  to  remember  that  neither  of 
these  of  itself  possesses,  practically  speaking,  any  illuminating 
power. 

E.  St.  Clair  Deville,  one  of  the  most  eminent  investigators  of  the 
day,  at  the  conclusion  of  a  long  and  brilliant  article  in  the  Journal 
of  Gas  Lighting,  for  1907,  says:  "The  author  is  of  the  opinion  that 
the  illuminating  power  in  the  incandescent  burner,  or  the  illumi- 
nating duty  of  a  gas,  expressed  in  candles  per  cubic  foot,  can  be 
defined  only  in  this  manner,viz. :  The  illuminating  duty  is  the  maxi- 
mum value  of  the  quotient  of  the  absolute  intensity  divided  by  the 

consumption,  or  - ,  when  a  particular  chosen  mantle  is  used.    When 
G 

this  value  is  divided  by  the  calorific  power,  c,  of  the  gas,  the  value 
obtained  represents  the  duty  in  terms  of  heat  expended.  It  is 
established  that  the  duty  obtained  for  the  expenditure  of  a  given 
number  of  units  of  heat  per  hour  remains  constant  within  15  per 
cent,  through  the  whole  range  of  illuminating  gases  from  neat  water 
gas  to  rich  cannel  gas.  The  slight  variations  to  which  this  duty  is 
subject,  appear  connected  with  the  corresponding  variations  in  the 
flame  temperature  of  the  gases.  The  duty  per  cubic  foot  of  gas 
consumed  is  very  nearly  proportional  to  the  calorific  power,  being 
subject  only  to  unimportant  variations  due  to  the  effect  of  flame 
temperature.  The  specific  or  normal  illuminating  duty  in  the 
incandescent  burner  is  proportional  to  the  calorific  power  of  the 
gas,  and  the  story  of  the  preponderating  part  played  by  the  flame 
temperature  must  no  longer  be  allowed  to  circulate." 

As  opposed  to  this,  experiments  reported  in  the  Journal  of  the 
American  Chemical  Society  for  October,  1906,  show  that  in  the 
work  of  the  writers  the  maximum  variations  of  flame  temperature 
from  calorific  power  was  as  low  as  2  per  cent.  Mr.  Isaac  Carr  of 
Widnes,  England,  says:  "It  has  often  been  said  that  calorific  value 
bore  no  relation  to  illuminating  power.  This  is  quite  true  when 


248 


GAS   AND   GAS   METERS 


comparing  gases  made  from  different  coal  fields  and  very  different 
methods  of  production ;  but  where  the  conditions  were  comparable, 
there  was  undoubtedly  a  relationship  between  illuminating  power 
and  calorific  value.  I  have  made  hundreds  of  tests  and  found  that 
the  calorific  value  rose  with  the  light-giving  quality  of  the  gas." 
Latta,  in  his  "American  Gas  Engineering  Practice,"  gives  the 
following  rather  remarkable  tables :  l 


Coal  Gas. 

Carburetted  Water  Gas. 

B  T.U. 

B  T  U 

Candle- 

Candle- 

power. 

Gross. 

Net. 

power. 

Gross. 

Net. 

12 

540 

480 

12 

490 

452 

13 

560 

500 

13 

510 

472 

14 

585 

522 

14 

529 

489 

15 

610 

542 

15 

547 

508 

16 

625 

562 

16 

567 

527 

i7 

647 

582 

I7 

587 

547 

18 

670 

603 

18 

607 

567 

iQ 

690 

622 

19 

627 

587 

20 

712 

642 

20 

647 

607 

According  to  this  table  there  is  a  constant  increase  of  from  20 
to  25  B.T.U.  for  each  increase  of  one  candlepower;  but  this  is  the 
only  table  which  the  writer  has  ever  seen  where  such  a  perfect 
relation  was  shown.  A  series  of  similar  purport,  though  less 
regular,  is  given  in  the  American  Gas  Lighting  Journal,  Feb- 
ruary 4,  1907,  and  is  here  inserted: 


Sample. 

Candlepower  with 
Argand  No.  i. 

Candlepower  with 
Argand  No.  2. 

Net  B.T.U.  per  cubic 
foot. 

A 

II.  50 

15.  26 

502.40 

B 

II.  70 

I5-7I 

518.43 

C 

12.08 

16.  15 

5I5-7I 

D 

12.36 

16.59 

525-40 

E 

12.96 

17.18 

530-  32 

F 

13.60 

J7-43 

537-41 

G 

14.  27 

17-85 

542.18 

H 

15.  10 

18.75 

554.52 

I 

15.  26 

18.54 

554-19 

Journal  of  Gas  Lighting,  February  26,  1907. 


CONSIDERATION   OF  RESULTS 


249 


Out  of  a  long  series  of  tests,  the  ensuing  are  selected  from  the 
reports  of  the  Massachusetts  State  Gas  Inspector: 


Candlepower. 

B.T.U. 

Candle- 
power. 

B.T.U. 

Candlepower. 

B.T.U. 

21.  I 

677.2 

19-3 

662.2 

27.0 

714.3 

23'7 

705-3 

22.6 

645-9 

26.2 

661.4 

23.2 

684.5 

21.0 

679.2 

26.2 

684.9 

24.2 

670.7 

2O.  O 

642.4 

23-3 

659-4 

21.6 

654.6 

19.8 

676.2 

25.0 

661.6 

23.1 

676.7 

20.8 

704.8 

24-5 

674.4 

21-3 

681.9 

21.4 

688.2 

19.1 

664.  i 

20.8 

687.4 

27.1 

691.  2 

21.4 

688.2 

Finally,  the  following  table  contains  the  results  of  tests  made  at 
various  places  throughout  New  York  State  in  1908,  no  two  tests 
being  of  gas  from  the  same  plant: 

WATER    GAS. 


Candle- 
power. 

B.T.U.  gross. 

Condensation. 

Candle- 
power. 

B.T.U.  gross. 

Condensation. 

21-3 

637.1 

45-0 

19.9 

620.3 

33-8 

14.9 

553-9 

23.0 

21.3 

692.7 

38.5 

20.8 

589.6 

25.0 

23-4 

624.4 

42.5 

19.8 

652.8 

36.3 

19.4 

566.0 

47.0 

19.9 

652.7 

41.9 

21.5 

610.0 

29.  o 

20.0 

622.3 

38.5 

23.6 

623-5 

38.0 

20.  2 

620.9 

.    41-7 

21.0 

569-5 

35-o 

27.1 

802.5 

47-3 

20.  9 

624.  o 

39-o 

COAL    GAS. 


Candle- 
power. 

B.T.U.  gross. 

Condensation. 

Candle- 
power. 

B.T.U.  gross. 

Condensation. 

12.3 

550-7 

50.6 

16.  o 

657.5 

68.0 

16.9 

622.6 

45-8 

14.4 

647.0 

63.0 

15-6 

717.9 

67-4 

17.9 

690-5 

67.0 

16.4 

7I3-5 

63-3 

13.0 

592-0 

54-o 

19.4 

703-4 

66.4 

16.  i 

577-o 

54-0 

14.9 

661.5 

59-9 

16.  4 

642.  o 

49-o 

I7.8 

663-3 

64.6 

16.  o 

659.0 

59-o 

12.  0 

552-0 

52.0 

16.  i 

627.  o 

62.  o 

I3.6 

559-0 

58.0 

16.5 

638.0 

69.0 

l8.3 

670.5 

57-0 

18.4 

674.0 

65.0 

16.2 

583-5 

52.0 

14.7 

616.  o 

54-0 

16.  i 

590.5 

59-o 

16.  i 

623-5 

58.4 

14.1 

626.0 

62.0 

13.0 

632.0 

58.0 

16.5 

671.  o 

58.0 

16.4 

659.0 

58.0 

15-7 

647.0 

55-o 

13-3 

605.0 

57-o 

CHAPTER  IV. 


PRESSURE  AND  SPECIFIC   GRAVITY. 

THE  pressure  at  which  gas  is  delivered  is  one  of  the  most  impor- 
tant factors  in  a  satisfactory  service;  and  in  connection  therewith, 
there  are  two  points  to  be  considered :  first,  the  pressure  should  be  as 
uniform  as  possible,  and  second,  it  should  be  neither  too  high  nor 
too  low.  The  first  point  is  possibly  the  more  important,  since  the 
evil  effects  of  too  high  pressure  can  be  guarded  against  by  the  con- 
sumer himself,  and  too  low  a  pressure  is  rarely  met.  If  the  pressure 
is  not  uniform,  however,  all  burners  and  stoves  will  be  out  of  adjust- 
ment most  of  the  time,  and  company  and  consumer  will  alike  suffer. 
Too  low  a  pressure  means  too  small  a  supply  of  gas  and  consequent 
inefficient  service  as  to  illuminating  and  heating  effects;  if  the 
pressure  be  too  high,  the  average  consumer  will  waste  his  gas  by 
allowing  burners  and  stoves  to  blow;  he  will  thus  receive  less  heat 
and  light,  while  paying  larger  bills,  and  is  pretty  certain  to  complain 
of  unfair  treatment  by  the  gas  company. 

Just  what  is  the  most  desirable  pressure  to  maintain  is  a  disputed 
point.  Research  has  seemed  to  show  that  the  Welsbach  burners 
operate  more  efficiently  at  a  higher  pressure,  as  may  be  partly 
gathered  from  the  following  table :  1 

PRESSURE    i.  2". 


Burner. 

Illuminating 
power,  candles. 

Consumption, 
cu.  ft. 

Efficiency. 

Welsbach  C  
Veritas  C 

40.  o 
24  o 

3.80 
3.  3O 

10.5 
7    3 

Compactum 

12    O 

T.    T.2Z 

3.6 

Bray  (with  Welsbach)  
Kern  
Inverted  

32-5 
47.0 

45  -° 

2.90 

3-35 

2-45 

II.  2 
14.0 
18.4 

Journal  of  Gas  Lighting,  April  2,  1907. 
250 


PRESSURE   AND   SPECIFIC    GRAVITY 

PRESSURE     2" 


251 


Burner. 

Illuminating 
power,  candles. 

Consumption, 
cu.  ft. 

Efficiency. 

Welsbach  C  

78-5 

4-95 

15-85 

Veritas  C  

60.  o 

4-25 

14.  10 

Compactum  

49-5 

4.325 

ii.  40 

Bray  and  mantle  

53-5 

3-9° 

13.70 

Kern  ... 

54-0 

4-375 

I2-35 

Inverted  

58.0 

3-20 

18.  10 

PRESSURE     2.1 


Welsbach  C  

107.  o 

6.  oo 

17-85 

Veritas  C  

90.  o 

5.10 

i7-65 

Compactum              '   . 

76.  o 

i;  20 

14.  60 

Bray  and  mantle  

55-° 

4.  10 

13.40 

Kern  

57-° 

4.  60 

12.  40 

Inverted  

60.  o 

3-825 

r5-7° 

The  very  latest  evidence,  however,  gathered  from  a  large  number 
of  experiments  by  Professor  McCormack  of  Chicago,  proves,  at 
least  in  the  opinion  of  the  experimenter,  that  2.3  inches  is  the  most 
satisfactory  pressure  for  incandescent  burners.1 

For  mantle  lamps,  gas  arcs,  etc.,  the  Wisconsin  Gas  Association 
believes  a  high  pressure,  say  3  to  4  inches,  improves  the  candlepower, 
but  that  for  all-round  use,  the  limits  should  be  2.5  to  4  inches, 
although  in  one  place  in  Wisconsin  a  normal  pressure  of  32  inches  is 
carried  and  gives  satisfaction.  The  Railroad  Commission  of  Wis- 
consin, in  its  recently  issued  rules,  prescribes  as  follows:  "  Gas  pres- 
sure, as  measured  at  meter  inlets,  shall  never  be  less  than  i  J  inches, 
nor  more  than  6  inches  of  water  pressure,  and  the  daily  variation  of 
pressure  at  the  inlet  of  any  one  meter  on  the  system  shall  never  be 
greater  than  100  per  cent  of  the  minimum  pressure."  The  Second 
Class  Cities'  law  in  New  York  State  requires  a  minimum  of  I J  inches 
and  a  maximum  of  3!  inches,  with  an  allowance  of  i  inch  for  every 
100  feet  in  altitude  above  the  holder.  This  allowance  is  due  to  the 


1  American  Gas  Light  Journal,  November  23,  1908. 


252  GAS   AND   GAS   METERS 

fact  that  gas,  on  account  of  its  low  specific  gravity  as  compared 
with  air,  increases  its  pressure  by  a  definite  amount  for  each 
increase  in  altitude  in  the  distributing  system. 

Mr.  A.  E.  Forstall  states  the  case  thus :  The  drop  in  the  pressure 
from  the  end  of  the  service  to  the  burner  orifice  is  about  0.7  inch. 
With  stoves,  it  is  necessary  for  good  results  that  the  pressure  at  the 
burner  orifice  shall  be  at  least  i  inch;  therefore,  a  minimum  of  1.7 
inches  must  be  constantly  maintained  in  the  main.  This  also  holds 
good  for  incandescent  burners.  Any  company  which  allows  its 
pressure  in  the  mains  to  drop  below  1.5  inches  is  certain  to  have  an 
enormous  number  of  complaints.  Mr.  Forstall  does  not  believe 
that  there  should  be  any  maximum  limit  for  pressure. 

A  minimum  allowance  of  ij  inches  seems  to  meet  with  but  little 
criticism,  but  the  writer  cannot  admit  that  there  should  be  no  maxi- 
mum limit  set.  An  experience  in  one  city  where  the  gas  company 
was  more  bitterly  attacked  than  in  any  other  place  in  the  state,  led 
to  an  investigation  which  seemed  to  prove  conclusively  that  the 
whole  source  of  the  trouble  lay  in  a  pressure  which  was  very  often 
between  5  and  6  inches,  and  in  several  instances  did  not  fall  far 
short  of  7  inches. 

If  the  consumer  could  be  educated  to  the  use  of  Welsbach  man- 
tles, and  to  the  proper  regulation  of  stoves  and  burners,  it  is 
probable  that  no  difficulty  would  be  experienced  with  these  high- 
pressures;  but  so  long  as  flat-flame  burners  (and  many  of  them  of 
antiquated  or  utterly  unsatisfactory  type)  are  in  use,  and  the  con- 
sumer persists  in  opening  wide  the  gascock,  so  long  will  there 
be  disputes  and  hard  feeling  between  the  public  and  the  gas 
company. 

All  that  has  been  said  thus  far  applies  to  coal  and  water  gas 
companies,  and  the  pressures  are  expressed  in  terms  of  the  height 
in  inches  of  a  column  of  water  which  would  be  supported  by  the 
pressure  in  question.  With  acetylene,  the  insurance  regulations 
require,  first,  that  the  working  pressure  at  the  generator  must  not 
vary  by  more  than  \%  (i)-inch  water  column  under  all  conditions 
of  carbide  charge  and  feed,  and  between  the  limits  of  no  load 
and  50  per  cent  overload;  and  second,  that  apparatus  not  requiring 


PRESSURE   AND   SPECIFIC   GRAVITY  253 

pressure  regulators  must  be  so  arranged  that  the  gas  pressure 
cannot  exceed  6  inches  water  column. 

Dr.  Lewes  says:  "On  consuming  acetylene  from  a  ooo  U.  J. 
burner  at  all  ordinary  pressures,  a  smoky  flame  is  obtained,  but 
on  increasing  the  pressure  to  4  inches  a  magnificent  flame  results, 
free  from  smoke  and  developing  an  illuminating  power  of  240 
candles  per  5  cubic  feet  of  gas  consumed."  It  seems  doubtful, 
however,  whether  such  a  pressure  is  in  any  way  common  among 
acetylene  plants  in  this  country.1 

With  natural  gas,  much  higher  pressures  are  necessary,  due 
partly  to  the  distances  which  the  gas  has  to  be  transported,  partly 
to  the  decreased  supply  in  the  winter  months,  and  partly  to  the 
fact  that  it  has  not  seemed  economical  or  desirable  to  cut  too 
heavily  the  natural  pressure  at  which  the  gas  issues  from  the  wells. 
Thus  natural  gas  is  frequently  supplied  under  pressures  ranging 
from  10  to  26  inches  of  water  column,  and  for  this  reason  the 
gauges  are  generally  filled  with  mercury  instead  of  water.  Since 
mercury  has  a  specific  gravity  of  13.56  at  15°  C.,  a  gas  pressure  of 

26  inches  water  will  only  be  equivalent  to ,  or  1.02  inches  mer- 

I3-56 

cury.  Pressure  in  the  natural  gas  fields  is  also  often  expressed 
in  ounces,  and  to  aid  in  the  comparison  of  these  three  forms  of 
measurement,  a  table  will  be  found  in  the  appendix. 

There  are  three  general  methods  in  vogue  to-day  for  taking  gas 
pressures :  by  the  Bristol  recording  gauge,  by  the  siphon  or  U  gauge, 
or  by  an  apparatus  similar  in  principle  to  King's  pressure  gauge 
and  sometimes  called  the  arch  pressure  gauge.  The  Bristol 
gauge  (Figs.  40  and  41),  is  an  instrument  designed  for  the  con- 
tinuous automatic  recording  of  gas  pressures.  The  record  is 
made  on  a  paper  chart  divided  on  its  circumference  into  hours, 
radial  arcs  reaching  from  these  points  to  the  center.  From  the 
center  towards  the  edge  are  concentric  circles,  each  representing 
0.2  inch  pressure.  The  chart  is  revolved  by  clockwork  in  the 

1  As  nearly  as  the  writer  can  learn,  3  inches  seems  to  be  the  pressure  generally 
recommended  by  managers  of  acetylene  plants,  as  shown  by  their  testimony  at  the 
meeting  of  the  International  Acetylene  Association  in  August,  1908. 


254  GAS   AND    GAS    METERS 

upper  part  of  the  case;  below  this  is  placed  a  series  of  diaphragms, 
A  A,  to  the  top  of  which  is  connected  the  arm,  C,  which  carries  the 
recording  pen.  The  operation  of  this  instrument,  as  described 
by  the  manufacturers,  is  as  follows:  "  Pressure  applied  to  the  system 
of  diaphragms,  A,  has  a  tendency  to  elongate  the  whole.  This 


Fig.  40.     Bristol  Pressure  Gauge,  Interior  View. 

tendency  is  resisted  by  the  flexible  strip,  B,  and  the  result  is  a 
multiplied  side  motion  sufficient  to  record  directly  by  means  of 
an  inking  pointer." 

The  gas  supply  is  connected  to  the  tube  at  the  bottom  of  the 
case.  To  start  the  instrument,  when  in  position,  it  is  only  neces- 
sary to  wind  the  clock,  place  a  chart  upon  the  face  and  clamp  it 


PRESSURE   AND   SPECIFIC    GRAVITY 


255 


in  position  by  the  center  thumb  nut,  fill  the  pen  with  ink  and  turn 
on  the  gas.  Set  it  on  zero  pressure  and  at  the  proper  hour  of  the 
day.  The  chart  takes  a  record  for  24  hours,  when  a  fresh  one 
may  be  substituted.  The  pen  must  be  cleaned  occasionally  and 
filled  with  special  ink  furnished  with  the  instrument. 


Fig.  41.     Bristol  Pressure  Gauge. 

It  is  well  to  standardize  this  gauge  frequently  by  comparison 
with  an  accurate  U  gauge,  as  it  is  always  possible  that  the  dia- 
phragms or  arm  may  have  become  bent,  or  be  working  improperly. 
The  arm  and  pen  must  be  handled  with  great  care,  and  when  the 
latter  is  not  actually  recording,  a  blank  chart  should  be  placed 
under  it  to  protect  the  point.  The  instrument  is  to  be  set  up  in  a 


256  GAS   AND   GAS   METERS 

level  position  and  preferably  screwed  against  the  wall  where  there 
is  no  vibration.  The  entire  apparatus  is  eminently  satisfactory, 
and  the  price  is  $50. 

The  siphon  or  U  gauge  is  one  of  the  simplest  and  most  accurate 
contrivances  employed  in  the  testing  of  gas.  It  consists  (Fig.  42), 
of  a  glass  tube  bent  into  the  form  of  a  narrow  U,  one  arm 
^^  of-  which  is  connected  by  a  nickel  tube  with  the  gas 
supply.  Between  the  two  arms  is  a  thin  wooden  scale 
graduated  in  inches,  with  the  zero  mark  in  the  center 
and  the  numbers  running  both  up  and  down  the  scale. 
The  tube  is  filled  with  water  up  to  the  zero  mark  in 
both  arms.  When  the  gas  is  turned  on  the  water  in  the 
right-hand  limb  is  forced  down,  while  that  in  the  left- 
hand  limb  rises.  The  air  displaced  by  the  rising  water 
escapes  through  a  small  hole  in  the  nickel  cap  at  the 
top  of  the  left-hand  arm.  It  is  then  only  necessary  to 
record  the  difference  in  height  of  the  water  in  the  two 
arms,  and  the  result  is  the  pressure  of  the  gas  in  inches 
of  water. 

The  scale    must   be    accurately   graduated,    but   the 
diameter  of  the  glass  tube  is  unimportant,  since  pressure 
Fig,  42.   exerted  on  a  liquid  is  transmitted  undiminished  in  all 
Siphon  on  directions  and  acts  with  equal  force  upon  all  surfaces  of 
U  Gauge.    j'ke  area4     The  COSf-  Of  a  6_jnch  gauge,  which  is  the 

right  size  for  nearly  all  city  pressures  with  artificial  gas, 
is  $1.75;  for  works'  use  a  14-inch  gauge  is  often  needed,  and  this 
costs  $5.50. 

The  arch  pressure  gauge,  as  seen  in  Fig.  43,  depends  for  its 
action  upon  the  rise  and  fall  of  a  float,  the  motion  being  transferred 
to  a  pointer  revolving  along  a  semi-circular  scale.  The  rectangular 
box  at  the  base  contains  water,  which,  by  the  pressure  of  the  gas, 
is  forced  up  in  the  cylinder,  causing  the  float  to  rise.  These 
instruments  were  more  popular  in  the  past  than  at  present;  a 
6-inch  gauge  costs  $32. 

Numerous  other  styles  of  gauges,  such  as  the  King's,  Simmance- 
Abady,  Alexander  Wright  &  Co.'s  Portable  Register,  Wright's 


PRESSURE   AND    SPECIFIC    GRAVITY 


257 


Register  and  Crosby's  Register,  are  manufactured  and  sold  in 
England,  but  are  not  frequently  met  in  this  country.  Should  any 
reader  be  interested  in  these,  he  should  consult  Alexander 
Wright  &  Co.'s  splendid  catalogue. 

One  final  precaution  must  be  mentioned  before  leaving  this 
subject.  It  is  a  too  common  practice  to  take  the  pressure,  with  a 
U  gauge,  at  the  burner  in  a  private  house,  and  then,  if  the  result 


Fig.  43.     Arch  Pressure  Gauge. 

proves  low,  to  criticise  the  gas  company.  Now  it  may  be  the 
latter's  fault;  but  there  is  also  an  excellent  chance  that  the  trouble 
may  be  due  to  stoppages  in  the  pipes  or  meter,  the  former  especially 
if  the  house  is  old  and  the  pipes  have  never  been  cleaned.  This 
may  seem  a  trivial  and  unnecessary  precaution;  but  the  writer  has 
seen  many  cases  where  it  applied,  and  especially  one  where  a  long 
and  costly  suit  against  the  gas  company  was  barely  averted  by  the 


258  GAS   AND   GAS   METERS 

discovery  that  the  complainant  had  been  securing  the  pressure 
results  of  which  he  complained  in  an  old  house  where  the  pipes 
were  badly  choked.  Tests  of  the  pressure  in  the  surrounding 
neighborhood  proved  the  error  of  his  figures  and  saved  trouble 
and  expense  to  both  company  and  consumer. 

Specific  Gravity.  The  specific  gravity  of  a  gas  is  the  ratio  which 
the  weight  of  a  given  volume  of  it  bears  to  the  weight  of  an  equal 
volume  of  air  (or  hydrogen)  under  similar  conditions  of  tempera- 
ture and  pressure.  In  considering  the  specific  gravity  of  illuminat- 
ing gas,  air  is  almost  universally  taken  as  a  standard;  but  in  scien- 
tific work,  especially  along  chemical  and  physical  lines,  hydrogen 
is  frequently  used.  The  determination  of  this  property  of  the 
gas  is  of  value  along  three  lines.  In  the  first  place,  it  is  a  necessary 
factor  in  the  calculation  of  the  flow  of  gas  in  pipes,  as  will  be  seen 

from  the  formula  Q  =  1350  d?U — ,  where  d  equals  the  diameter 

of  the  pipe  in  inches,  h  equals  the  pressure  in  inches  of  water, 
/  equals  the  length  of  the  pipe  in  yards,  5  equals  specific  gravity  of 
the  gas  (air  equaling  i);  and  Q>  the  quantity  of  gas  in  cubic  feet 
per  hour  which  will  flow  through  the  pipe  under  the  given  con- 
ditions. In  the  second  place,  it  sometimes  happens  that  the  gas 
manager  desires  to  know  the  weight  of  gas  produced  from  a  given 
weight  of  coal;  here  the  specific  gravity  is  clearly  indispensable. 
Third,  it  furnishes  some  clue  to  the  nature  and  amount  of  impurities 
in  the  gas.  This  arises  from  the  fact  that  the  gravity  of  each  of 
the  common  impurities  is  far  greater  than  that  of  the  gas  itself. 
Thus,  coal  gas  has  a  specific  gravity  of  about  0.45  and  water  gas 
of  about  0.66;  the  figure  for  nitrogen  is  0.97;  for  oxygen  i.n;  for 
hydrogen  sulphide  1.18;  and  for  carbonic  acid,  1.53;  so  that  a 
considerable  increase  in  the  per  cent  of  either  or  all  of  these  is 
certain  to  have  its  effect  on  the  specific  gravity  of  the  finished 
product. 

Several  pieces  of  apparatus  have  been  devised  for  use  in  deter- 
mining the  specific  gravity  of  gas,  all  of  which  depend  upon  an 
actual  weighing  of  equal  volumes  of  gas  and  air  inclosed  in  detached 
glass  globes.  This  requires  an  extremely  sensitive  balance,  and 


PRESSURE  AND   SPECIFIC   GRAVITY 


259 


the  apparatus  is  delicate  and  costly;  these  processes  are  therefore 
utterly  unfitted  for  gas  works'  use.  There  are  only  two  methods 
in  very  general  use  in  this  country,  so  far  as  the  writer  knows,  the 
one  using  the  Lux  balance  and  the  other  employing,  in  principle 
at  least,  the  effusion  test  of  Bunsen. 

The  Lux  balance  (Fig.  44)  consists  of  a  large  glass  bulb,  A, 
attached  to  one  end  of  the  lever,  B.  This  lever  has  its  fulcrum  in 
the  support,  C,  and  its  other  end  is  pointed  and  travels  along  the 


Fig.  44.     Lux  Balance. 

arc,  D,  which  is  so  graduated  that  the  direct  readings  of  specific 
gravity  may  be  made  therefrom.  The  gas  enters  the  bulb  through 
E  and  is  discharged  through  F. 

To  use  this  instrument  after  it  is  once  adjusted  and  calibrated 
it  is  only  necessary  to  completely  fill  the  bulb  with  the  gas  to  be 
tested  to  the  exclusion  of  all  air,  and  observe  the  reading  indicated 
on  the  scale  by  the  pointer.  Corrections  must  be  made  for  the 


260 


GAS   AND   GAS   METERS 


temperature  and  pressure,  and  these  Abady  states  as  follows: 
"For  every  millimeter  at  which  the  barometer  stands  above  or 
below  760  millimeters,  0.0007  is  added  or  deducted  from  the  specific 
weight  indicated  on  scale.  For  every  degree  Centigrade  at  which 
the  thermometer  stands  above  or  below  15  degrees,  0.002  must  be 
deducted  or  added. " 

This  method  takes  no  account  of  the  moisture  in  the  gas,  and 
a  true  scientific  determination  of  specific  gravity  ascertains  the 
relation  between  dry  gas  and  dry  air.     This,  however,  is  a  refine- 
ment which  does  not  seem  necessary  for  gas  works'  use,  and  the 
figures    obtained   with    the    Lux   balance 
should    be    sufficiently    accurate    for    all 
practical  purposes. 

If  it  is  desired  to  calibrate  the  instru- 
ment in  the  laboratory,  fill  the  bulb  with 
air  at  15°  C.  and  760  mm.  pressure,  and 
mark  the  point  on  the  scale  indicated  by 
the  pointer  as  i.  Then  fill  the  bulb  with 
hydrogen  at  the  same  temperature  and 
pressure;  the  position  of  the  pointer  in  this 
case  should  be  marked  0.07.  The  space 
between  these  two  points  is  then  subdi- 
vided, and  the  scale  is  ready  for  use.  The 
cost  of  the  Lux  balance  is  $170.00. 

The  Bunsen  effusion  test  is  based  on 
the  fact  that  the  specific  gravities  of  two 
gases  are  inversely  proportional  to  the 
squares  of  the  speeds  with  which  they 
escape  through  a  minute  opening  in  a 
thin  plate.  This  ratio  is  not  absolutely 
correct,  but  is  near  enough  for  all  practical 
purposes.  Mr.  W.  W.  Goodwin  made  a 
series  of  experiments  on  this  subject,  with 

various  gases,  and  found  that  this  method  gave  results  which  dif- 
fered from  the  theoretical  figures  by  less  than  0.016  in  all  cases  but 
one.  In  the  exception,  one  volume  of  carbon  monoxide  plus  one 


Fig.  45.    Schilling's  Speci- 
fic Gravity  Apparatus. 


PRESSURE   AND   SPECIFIC   GRAVITY  26 1 

volume  of  carbonic  acid  was  used,  and  the  specific  gravity  as  deter- 
mined experimentally  was  1.203,  while  the  theoretical  result  is  1.244. 

The  apparatus  generally  used  is  shown  in  Fig.  45.  It  consists 
of  a  glass  jar,  A,  which  when  in  use  is  filled  with  water;  a  glass 
tube,  By  which  is  graduated,  and  employed  for  the  measurement 
of  the  gas;  a  movable  cap,  C,  and  a  tip,  E,  which  contains  the 
fine  orifice  through  which  the  gas  is  to  escape. 

In  using  this  instrument  first  remove  the  tube,  B,  and  fill  the 
cylinder,  A,  with  water  up  to  a  point  slightly  above  the  level  of  the 
upper  mark  on  B  when  the  latter  is  in  place.  Close  the  cock 
above  B  and  insert  the  tube  in  its  place,  where  it  is  held  in  position 
by  a  catch.  Now  having  a  stop  watch  ready  in  the  hand,  open 
the  cock,  and  as  the  water  rising  in  the  tube  passes  the  line  marked 
i,  start  the  watch.  When  the  surface  line  of  the  water  exactly 
reaches  some  other  mark,  say  10,  the  watch  is  to  be  stopped  and 
the  time  recorded.  Repeat  the  experiment,  using  gas  instead  of 
air,  and  being  certain  that  all  air  has  been  expelled  from  the 
apparatus  and  that  the  water  is  saturated  with  the  gas  to  be  tested. 

The  specific  gravity  of  the  gas  is  then  obtained  from  the  for- 
mula S=  —  where  G  =  the  time  in  seconds  consumed  by  the  gas 

A. 

in  passing  from  line  i  to  line  10;  A  =  the  corresponding  time  for 
the  air. 

Example.    Gas  took  81  seconds;  air  127  seconds. 

Specific  gravity  =  -^  =  0.407. 

This  apparatus  is  furnished,  in  a  neat  carrying  case,  for  $20. 

Slightly  different  is  the  apparatus  used  by  the  inspectors  of 
Massachusetts  and  New  York  for  specific  gravity  determina- 
tions. It  consists  of  two  large  perforated  rubber  stoppers,  each 
having  a  brass  tube  projecting  laterally  near  the  large  end,  and 
connecting  with  the  hole  in  the  stopper.  A  glass  piece  in  the 
form  of  a  truncated  cone  fits  tightly  over  one  stopper;  it  is 
9  inches  long,  i|  inches  diameter  at  the  base  and  i  inch  at  the 
top.  A  similarly  shaped  piece  9  inches  long  by  ij  inches  diam- 


262 


GAS  AND   GAS  METERS 


eter  at  the  lower  end  fits  over  the  second  stopper;  2  inches  above 
the  latter  the  tube  has  a  construction  i  inch  in  diameter,  and  at 
its  upper  part  is  narrowed  to  a  neck  five-sixteenths  inch  in  diam- 
eter which  is  ground  on  the  inside  to  receive  the  end  of  a  tube 

7J  inches  long  and  one-fourth 
inch  in  diameter,  in  the  upper  end 
of  which  is  fitted  a  platinum 
plate  containing  the  emission 
orifice.  One  and  three-fourths 
inches  below  this  plate  is  a  three- 
way  glass  stopcock,  and  3  inches, 
below  the  latter  a  scratch  sur- 
rounds the  tube  and  serves  as  the 
upper  mark  in  the  escape  of  the 
gas. 

Fitted  into  the  hole  in  the 
stopper  is  a  hollow  cylinder  of 
brass  to  which  is  soldered  a 
curved  piece  of  brass  wire 
pointed  at  the  end,  which  rises 
ij  inches  above  the  surface  of 
the  stopper.  The  two  brass 
tubes  projecting  from  the  out- 
side of  the  stoppers  are  joined 
by  a  piece  of  rubber  tubing  15  to 
1 8  inches  long. 

In  using  this  instrument  the 
larger  tube  is  filled  with  water, 
of  the  temperature  of  the  room, 
nearly  to  the  top,  the  stopcock 

being  turned  so  that  egress  of  air  from  the  smaller  tube  is  pre- 
vented. The  larger  tube  is  placed  on  an  elevated  surface  just 
high  enough  so  that  its  bottom  is  above  the  level  of  the  scratch 
on  the  narrow  outlet  tube,  the  cock  is  turned  so  that  the  air  may 
escape  through  the  orifice  in  the  platinum  plate,  and  at  the  second, 
when  the  point  of  the  brass  wire  breaks  the  surface  of  the  rising 


Fig.  46.    Jenkin's  Specific  Gravity 
Apparatus. 


PRESSURE   AND   SPECIFIC    GRAVITY  263 

water,  a  stop  watch  is  started.  The  latter  is  stopped  when  the 
water  exactly  reaches  the  scratch. 

The  large  tube  is  lowered,  and  the  stopcock  turned  so  air  may 
enter  through  its  hollow  point.  When  the  water  is  again  all  in 
the  large  cylinder,  the  cock  is  turned  to  connect  the  small  vessel 
with  the  outside  air  through  the  platinum  tip,  the  large  cylinder 
is  replaced  on  the  elevation  and  the  operation  repeated.  Results 
should  be  obtained  which  check  within  one-fifth  second. 

Now  connect  a  rubber  tube  to  the  gas  supply  and  to  the  tip  of 
the  stopcock,  lower  the  large  cylinder  and  force  the  water  into  the 
latter  by  means  of  the  gas  pressure.  Thoroughly  saturate  the 
water  with  the  gas  to  be  tested;  this  may  be  done  by  shaking 
gas  and  water  together  and  by  forcing  the  water  up  and  down  in 
the  small  vessel  in  contact  with  the  gas.  Repeat  the  operations 
with  gas  in  the  same  manner  as  described  for  air.  The  calcu- 
lation is  made  in  exactly  the  way  already  described  for  the  Bunsen 
or  Schilling  test. 

The  advantages  of  this  apparatus  are  its  portability,  its  cheap- 
ness, its  rapidity  and  accuracy.  When  set  up,  the  cylinders  are 
inclined  to  be  a  trifle  unstable;  this  may  be  overcome  by  fasten- 
ing a  lead  plate  to  the  base  of  each  stopper.  The  writer  has  also 
substituted  a  copper  cylinder  for  the  larger  glass  vessel  with 
satisfactory  results.  The  entire  outfit  weighs  less  than  i  J  pounds, 
and  costs  about  $3.70.  Four  precautions  in  connection  with  its 
use  should  be  emphasized:  (i)  The  water  must  be  of  the  room 
temperature;  (2)  the  water  must  be  thoroughly  saturated  with 
the  gas;  (3)  the  platinum  tip,  stopcock,  and  upper  part  of  the 
tube  must  be  kept  dry  and  clean;  (4)  the  large  cylinder  must 
always,  in  any  one  determination,  be  placed  at  the  same  height. 
Of  these  precautions  Nos.  i,  2  and  3  apply  equally  well  to  the 
use  of  the  Schilling  instrument.  If  care  is  taken  results  may 
easily  be  obtained  which  check  to  within  one-fifth  second;  a 
variation  of  the  latter  amount  means  on  a  coal  gas  of  specific 
gravity  0.42,  only  about  o.ooi  in  the  final  result. 

Specific  gravity  is  sometimes  determined  from  the  analysis  of  a 
gas,  by  calculations.  The  usual  method  of  procedure  is  to  mul- 


264  GAS   AND   GAS   METERS 

tiply  the  per  cent  of  each  constituent  by  its  specific  gravity,  add 
the  products  and  divide  by  100.  This  is  not  as  accurate  or  satis- 
factory as  an  actual  determination,  but  may  be  needed  to  furnish 
approximate  results  in  certain  cases. 

The  results  of  specific  gravity  determinations  will  necessarily 
vary  with  varying  conditions,  and  the  most  that  can  be  done  to 
show  what  may  be  expected  is  to  illustrate  by  certain  figures 
which  have  been  reached.  For  coal  gas,  results  from  various 
sources  are  from  0.380  to  0.574;  the  latter  figure,  however,  is 
extraordinary,  and  was  obtained  with  a  coal  gas  of  over  22  candle- 
power  (the  specific  gravity  of  coke-oven  gas  is  given  as  0.508). 
0.380  is  a  very  low  figure,  and  came  from  a  gas  of  only  13.4 
candlepower. 

In  general  the  specific  gravity  of  coal  gas  seems  to  be  between 
0.400  and  0.460,  although  it  may  run  beyond  these  in  either 
direction. 

Blue  water  gas  has  a  specific  gravity  of  about  0.431,  while  for 
carburetted  water  gas  the  figure  is  generally  between  0.600  and 
0.700.  In  an  article  in  the  Journal  of  Gas  Lighting,  for  Jan.  14, 
1908,  the  specific  gravity  of  carburetted  water  gas  is  given  as  0.528, 
but  this  figure  seems  to  the  writer  to  be  far  too  low. 

Mixed  gas  will  of  course  vary  in  specific  gravity  according  to  the 
proportions  and  gravities  of  the  water  and  coal  gas  used,  so  that  any 
general  statement  attempting  to  cover  this  point  would  be  valueless. 

Oil  gas  of  50  candlepower  may  have  a  specific  gravity  of  0.850- 
0.880,  although  this  figure  also  is  necessarily  tentative. 

Pure  acetylene  has  a  specific  gravity  of  0.8982,  and  the  commer- 
cial article  will  not  vary  much  from  this. 

Natural  gas  varies  greatly  in  gravity,  according  to  its  source  and 
composition;  in  one  of  the  Pennsylvania  fields  the  writer  obtained 
results  between  0.707  and  0.717.  The  whole  question  of  specific 
gravity,  however,  has  its  greatest  field  in  connection  with  the 
routine  determinations  of  one  kind  of  gas,  in  which  case  a  com- 
parison of  results  will  be  of  value;  further  consideration  is,  there- 
fore, left  to  the  analyst  and  manager  who  shall  make  and  interpret 
the  results  on  the  spot. 


PRESSURE   AND  SPECIFIC    GRAVITY  265 

The  so-called  Jet  photometers  are,  in  the  true  sense  of  the  word, 
not  photometers  (or  light  measurers)  at  all.  They  depend  for  their 
action  on  the  theory  that  a  change  in  the  specific  gravity  and  com- 
position of  the  gas  will  produce  a  proportionate  change  in  the  light 
of  a  long,  thin  and  pointed  flame,  supplied  by  gas  through  a  small 
orifice.  If  the  gas  to  be  tested  were  always  of  practically  the  same 
quality,  the  Jet  photometer  would  doubtless  reveal  that  fact;  but 
it  too  often  happens  that  a  gas  drops  from  18  to  14  candlepower, 
and  no  indication  of  such  change  is  recorded  by  the  jet.  This  is 
doubtless  partly  due  to  improper  care  of  the  instrument,  especially 
if  the  Jones  jet  be  used.  The  interior  of  the  chamber  is  allowed 
to  become  dirty  and  sticky,  and  the  glycerine  is  either  forgotten 
entirely  or  remembered  at  irregular  intervals. 

If  such  were  the  only  causes  of  inaccuracy,  however,  no  blame 
could  attach  to  the  instrument  itself.  Unfortunately,  the  trouble 
lies  deeper,  in  the  very  principle  of  the  apparatus,  for,  as  has  been 
already  indicated  in  the  chapter  on  Calorimetry,  the  gravity  and 
heating  value  of  the  gas  may  remain  almost  constant,  while  its  can- 
dlepower  may  wander  over  rather  wide  limits.  This  defect  of  the 
jet  photometer  has  been  repeatedly  proven  in  practical  work,  by 
comparing  its  readings  with  those  of  a  standard  bar  photometer, 
and  the  inaccuracy  of  the  jet  is  so  well  attested  to-day  that  it  is  rap- 
idly falling  into  disuse,  at  least  in  progressive  and  well-informed 
circles. 


PART  IV. 


TESTING  OF  METERS. 


PART  IV. 

TESTING    OF   METERS. 


CHAPTER  I. 
THE  CUBIC  FOOT  AND  METER  PROVER. 

As  has  been  mentioned  in  connection  with  gas  testing,  the  author 
has  endeavored  to  deal  only  with  the  finished  product.  The  same 
may  be  said  with  regard  to  meters.  It  is  not  within  the  scope  of 
this  work  to  treat  of  the  construction,  adjustment  or  other  mechan- 
ical features  connected  with  meter  manufacture.  All  that  will  be 
attempted  is  to  cover  briefly  but  carefully  the  testing  of  the  meter 
for  accuracy  of  registration,  and  this  only  after  the  meter  is  topped 
and  ready  for  service. 

It  is  a  curious  and  interesting  fact  that  while  gas  has  been  in  use 
in  England  for  one  hundred  years,  it  is  only  since  1861  that  meters 
have  been  subject  to  governmental  regulations  with  regard  to  their 
accuracy  of  registration  and  the  methods  and  apparatus  to  be 
employed  in  proving  them.  Thus  the  United  States  is  not  far 
behind  in  this  respect,  for  it  was  about  1865  that  Massachusetts 
appointed  an  inspector  of  gas  and  gas  meters.  This  example  has 
been  widely  copied  in  cities  and  states  throughout  the  Union,  and 
the  gas  companies  themselves,  perceiving  the  importance  of  the 
subject  and  the  advantages  accruing  therefrom,  have  almost  with- 
out exception  followed  suit,  so  that  to-day  it  may  be  said  that  few 
indeed  are  the  meters  which  are  installed  without  having  been  tested 
by  some  one. 

The  advantages  to  be  gained  from  such  procedure  are  twofold. 
First,  should  the  meter  be  fast,  or,  in  other  words,  register  against 
the  consumer,  disputes  and  hard  feeling  will  arise  between  the 

269 


2/0  GAS   AND    GAS   METERS 

latter  and  the  gas  company,  and  every  manager  will  appreciate  the 
importance  of  this.  Second,  if  the  meter  be  slow,  or  against 
the  company,  the  latter  is  delivering  goods  for  which  it  receives  no 
pay,  and  the  column  of  "unaccounted-for  gas"  will  grow. 

After  the  meter  has  been  in  service  for  some  time  it  may  either 
cease  to  register  at  all,  on  account  of  leakage,  etc.,  or  the  diaphragms 
may  dry  and  shrink,  and  the  record  of  the  dial  be  entirely  incorrect. 
Meters  are  frequently  set  in  either  very  hot  or  very  cold  places,  and 
this  is  a  bad  practice,  as  temperatures  below  40  degrees  or  over 
100  degrees  will  injure  the  oiled  leather  of  the  diaphragms. 

Moreover,  occasionally  a  mistake  in  the  factory  may  result  in  the 
wrong  dial  or  cogs  being  placed  in  a  meter.  Thus,  in  Toronto, 
Canada,  a  lo-light  dial  was  discovered  on  a  5-light  meter,  and  the 
rebate  which  the  company  offered  to  settle  the  claim  was  $360.  In 
New  York  State  a  shipment  of  meters  was  received  by  one  of  the 
companies,  and,  on  test  by  a  state  inspector,  it  was  discovered  that 
all  of  them  were  in  the  neighborhood  of  50  per  cent  fast.  On 
searching  for  the  cause,  it  was  found  that  the  wrong  cogs  had  been 
used  in  the  gearing. 

For  these  reasons  it  is  desirable  that  all  meters  should  be  tested 
at  stated  intervals,  and  it  is  becoming  a  more  and  more  general  cus- 
tom to  remove  all  meters  at  least  once  in  every  three  or  five  years. 
This  may  seem  to  be  an  expensive  operation,  but  it  has  been  proven 
by  experience  to  be  economical  in  the  long  run. 

The  still  more  recent  practice  of  oiling  the  meters  seems  to  be  an 
excellent  one,  as  it  not  only  prolongs  the  life,  but  also  lengthens  the 
period  during  which  the  meter  retains  its  original  accuracy;  but 
even  this  custom  will  not  obviate  the  desirability  of  testing  the 
meters  frequently. 

It  becomes  then  of -importance  to  learn  what  apparatus  is  required 
for  this  work,  how  it  should  be  used,  and  some  of  the  finer  points, 
which  are  in  reality  the  essential  ones,  of  meter  testing. 

The  Standard.  A  meter  is  tested  for  accuracy  of  registration 
by  passing  through  it  a  known  volume  of  air  or  gas  and  observ- 
ing the  effect  produced  on  the  dial  of  the  meter.  This  known 
volume  of  air  is  usually  forced  through  the  meter  from  a  meter 


UNIVERSITY 

OF 


THE   CUBIC   FOOT   AND   METER   PROVER 


271 


prover,  but  before  the  latter  can  be  employed  it  must  be  stand- 
ardized against  some  instrument  of  known  value.  Such  an 
instrument  is  the  standard  cubic  foot,  which  may  be  considered 
as  the  primary  standard,  or  court  of  last  appeal. 


Fig.  47.     Referees'  Cubic  Foot  Bottle. 

There  are  three  forms  of  the  standard  cubic  foot  in  use  to-day : 
the  one  recommended  by  the  Referees  and  used  in  London,  the 
cubic-foot  bottle  formerly  (and  still  to  some  extent)  used  in  the 
United  States,  and  the  modern  standard  cubic  foot  which  is  of 
comparatively  recent  invention,  and  which  seems  destined  to 
replace  the  older  forms.  Of  these  the  English  form,  which  is 
seen  in  Fig.  47,  is  intended  more  for  use  in  the  direct  testing  of 
meters,  and  so  will  not  be  described  here.  The  methods  em- 


GAS   AND   GAS   METERS 


Fig.  48.     American  Standard 
Cubic  Foot. 


ployed  with  this  instrument  will 
be  clear  from  the  diagram  and 
from  what  will  follow  regarding 
the  other  forms  of  standards; 
those  interested  in  this  subject, 
however,  should  consult  the 
Notification  of  the  Metropolitan 
Gas  Referees  for  1907  and 
1908. 

The  modern  standard  cubic 
foot  is  to  be  seen  in  Fig.  48.  It 
consists  of  an  oval  copper  vessel, 
a,  joined  at  the  top  and  bottom 
with  the  water  tanks,  b  and  c, 
respectively.  These  tanks  are  of 
wood,  metal  lined,  and  are  con- 
nected with  each  other  directly  by 
the  pipe,  d.  At  e  is  a  pump  which 
enables  the  water  to  be  forced 
from  the  lower  to  the  higher  tank ; 
/  is  a  funnel  through  which 
water  may  be  added;  and  g,  a 
cock  by  which  it  may  be  drawn 
off.  Immediately  above  and 
below  the  copper  vessel  are  two 
small  wooden  shelves  which  are 
fastened  to  the  wooden  back  of 
the  instrument  which  runs  from 
the  upper  to  the  lower  tank  and 
binds  the  whole  together. 

The  pipe  leading  from  the  cop- 
per vessel,  both  above  and  below, 
is  of  glass  for  about  six  inches, 
and  on  these  glass  portions  are 
marked  the  upper  and  lower  limits 
of  the  cubic  foot.  Six  inches 


THE    CUBIC    FOOT   AND    METER   PROVER  2/3 

above  the  upper  glass  tube  is  a  three-way  cock  and  a  small  tube,  h, 
which  permits  of  the  escape  of  air.  At  i  is  a  valve  by  which  the 
cubic  foot  may  be  shut  off  from  the  apparatus  under  test,  and  j 
is  a  similar  valve  for  controlling  the  flow  of  water  from  the  upper 
tank  to  the  copper  vessel;  k  is  a  three-way  cock  connecting  with 
the  lower  tank,  the  pipe,  m,  and  the  vessel  above;  n  is  a  threaded 
connection  by  which  the  cubic  foot  and  the  apparatus  to  be  tested 
may  be  joined.  The  standard  and  tanks  are  of  oak,  and  all  of 
the  piping  is  nickel  plated;  the  cost  of  the  apparatus  is  $300. 

Whenever  possible  it  is  desirable  to  have  this  cubic  foot  stand- 
ardized and  certified  by  the  National  Bureau  of  Standards  at 
Washington;  this  may  be  done  for  a  nominal  sum,  and  the 
operator  will  thus  be  certain  of  the  value  of  his  primary  standard. 
Should  one  desire  to  test  the  instrument  personally,  however,  this 
may  be  done  by  filling  the  vessel  up  to  the  mark  on  the  upper 
glass  tube  with  water  of  62°  F.,  letting  it  run  out  until  the  mark 
on  the  lower  gauge  glass  is  reached,  and  weighing  the  water  thus 
obtained.  The  apparatus  is  constructed  to  hold,  between  these 
two  marks,  exactly  62.279  pounds  of  water  at  62°  F.  and  30 
inches  pressure.  If  it  varies  from  this,  there  is  an  adjustment 
on  the  side  of  the  vessel  whereby  any  error  may  be  rectified. 

The  instrument  should  be  set  up  level  and  with  the  back  rest- 
ing against  a  solid  wall.  To  prepare  for  use  it  is  only  necessary 
to  fill  the  lower  tank  with  water  to  the  level  of  the  upper  cock, 
close  j  and  pump  the  water  into  the  upper  tank.  In  filling  the 
copper  vessel,  first  adjust  the  upper  three-way  cock  so  that  the 
only  exit  for  air  is  through  h.  Turn  k  to  connect  the  upper  tank 
with  the  vessel,  and  finally  open  j.  The  water  will  run  by  gravity 
from  the  upper  tank,  the  air  expelled  from  the  copper  vessel 
escaping  through  h.  When  the  water  has  risen  a  trifle  above  the 
mark  on  the  upper  gauge  glass,  close  j,  and  by  careful  manipu- 
lation of  k  the  level  of  the  water  may  be  brought  exactly  to  the 
mark  on  the  glass.  Now  turn  the  upper  three-way  cock  so  as  to 
connect  the  copper  vessel  with  the  prover  to  be  standardized, 
whose  valve  is  closed,  and  everything  is  ready  for  the  test. 

Little  need  be  said  regarding  the  care  of  the  cubic  foot.     It  is 


2/4  GAS   AND    GAS   METERS 

an  expensive  and  handsome  piece  of  apparatus  and  should  be 
treated  accordingly.  The  nickel  work  will  quickly  grow  dull 
on  standing  in  the  air,  and  this  should  be  prevented  by  frequent 
polishing.  The  copper  bell  should  likewise  be  kept  clean  and 
dry,  and  the  pump  and  all  valves  should  be  frequently  greased. 
If  the  cubic  foot  is  to  be  but  seldom  used,  it  is  well  to  draw  off 
the  water  after  finishing  a  test,  in  order  that  it  may  not  act  on  the 
lining  of  the  tanks,  pipes,  etc.  The  gauge  glasses  are  so  secured 
in  place  that  they  may  be  easily  removed  and  cleaned,  and  this 
should  be  done  whenever  necessary. 

The  so-called  water  bottle  is  still  employed  in  many  places,  and 
if  properly  handled  will  give  excellent  service.  It  consists  in 
general  of  a  cylindrical  copper  tank  about  3  feet  high  and  open  at 
the  top.  From  the  sides  two  posts  project  upwards  and  at  a 
height  of  some  6  feet  are  connected  by  a  cross  bar  sustaining  a 
wheel,  over  which  passes  a  steel  cord.  One  end  of  this  is  fastened 
to  a  weight  which  hangs  outside  the  line  of  the  cylindrical  tank, 
while  the  other  is  connected  to  a  hook  in  the  top  of  a  copper  vessel 
which  has  somewhat  the  shape  of  a  football  with  tapering  ends. 
This  vessel  or  bottle  has  an  opening  at  the  bottom  about  i  J  inches 
in  diameter,  while  at  the  top  the  only  opening  is  through  two 
valves  which  lead,  the  one  by  rubber  tubing  to  the  instrument  to 
be  tested,  and  the  other  to  the  open  air.  The  tank  is  filled  nearly 
to  the  top  with  water  of  the  temperature  of  the  room,  and  the 
apparatus  is  ready  for  use.  The  comparison  of  this  instrument 
with  the  modern  cubic  foot  will  be  reserved  until  after  the  actual 
operation  of  prover  testing  has  been  described. 

The  Meter  Prover.  There  are  many  types  of  provers  on  the 
market,  but  as  the  general  construction  and  operation  of  all  are 
practically  the  same,  but  one  kind  will  be  described,  although  an 
attempt  will  be  made  to  enumerate  the  points  of  difference  notice- 
able in  the  other  forms. 

A  prover  consists  (Fig.  49)  of  an  outer  tank,  a,  of  galvanized 
iron,  copper,  or  brass,  resting  upon  three  short  legs.  This  tank 
will  vary  in  dimensions  according  to  the  capacity  of  the  prover; 
for  a  5-foot  size,  it  will  be  about  32  inches  high  and  24  inches  in 


THE  CUBIC  FOOT  AND  METER  PROVER 


275 


Fig.  49,     Meter  Prover. 


2/6  GAS   AND    GAS   METERS 

diameter.  On  the  front  of  this  is  a  rectangular  pipe,  6,  which, 
passing  beneath  the  tank,  connects  the  bell  with  the  revolving 
valve,  c,  and  with  the  two  outlet  valves,  d  and  e.  This  pipe  is 
known  as  the  air  chamber,  and  serves  for  the  passage  of  air  from 
the  bell  either  to  the  room  by  the  valve,  c,  or  to  the  meter  to  be 
tested  by  the  valves,  d  and  e.  In  some  provers  this  air  chamber 
consists  of  a  cast-iron  pipe  of  about  ij  inches  diameter,  which  has 
certain  advantages  as  to  solidity  and  indestructibility,  but  which 
does  not  possess  the  capacity  of  the  rectangular  chamber.  On 
the  side  of  the  tank  opposite  to  the  air  chamber  is  a  faucet  whereby 
the  water  may  be  removed. 

Within  the  tank,  the  air  chamber  may  lead  above  the  surface  of 
the  water  by  either  of  two  methods.  First,  by  a  slender  pipe  of 
about  2  inches  diameter,  which  rises  directly  in  the  center  of  the 
tank,  or,  second,  by  a  hole  of  the  same  size  passing  through  the 
center  of  an  interior  shell  or  dome  which  is  closed  to  both  air  and 
water,  and  which  fills  nearly  the  entire  diameter  of  the  tank. 
This  second  method  would  seem  to  be  preferable  for  three  reasons, 
(i)  It  requires  less  water  to  fill  the  tank;  (2)  because  of  this  smaller 
volume  of  liquid,  it  is  easier  to  adjust  temperatures;  (3)  the  air 
chamber  is  well  protected,  whereas,  with  the  first  method,  the 
slender  tube  is  liable  to  be  bent  or  dented,  in  which  case  a  leak 
may  well  result. 

Three  posts  or  columns,  34  inches  long,  are  screwed  into  the 
upper  rim  of  the  tank  at  equal  distances  from  each  other;  these 
serve  to  support  the  cast-iron  tripod,/,  which  has  in  its  center  a 
large  circular  hole  through  which  the  chain  passes  to  the  top  of 
the  bell.  The  upright  cast-iron  bracket,  g,  bears  two  sets  of 
anti-friction  rolls,  on  which  rests  the  axis  of  the  large  wheel,  h, 
and  of  the  cycloid,  i.  The  tripod  is  held  in  place  by  acorns 
screwed  on  to  the  three  columns.  At  the  left  of  the  air  chamber 
a  nickel  scale  is  fastened  to  the  column  by  long  screws  which  pass 
through  the  latter  and  are  secured  in  place  by  thumb  nuts.  The 
chain,  j,  is  hooked  to  a  loop  projecting  from  the  center  and  top  of 
the  bell;  it  then  passes  over  a  groove  in  the  large  wheel  and  is 
fastened  at  its  other  end  to  the  weight,  k.  A  cord  passes  from  the 


THE  CUBIC  FOOT  AND  METER  PROVER 

end  of  the  cycloid,  through  a  groove  in  the  circumference  of  the 
latter,  to  the  nickel  weight,  m. 

The  bell,  n,  either  of  copper  or  galvanized  iron,  is  a  hollow 
cylinder  of  about  the  same  height  as  the  tank,  but  its  top  is  slightly 
dome-shaped,  and  this  portion  is  always  above  the  level  of  the 
outer  tank.  Placed  at  equal  intervals  on  the  top  and  bottom  are 
three  wheels  which  run  on  brass  rods  attached  to  the  columns 
and  to  the  interior  of  the  tank ;  this  insures  a  steady  vertical  motion 
to  the  bell.  To  the  wheel  running  on  the  left  front  column  is 
attached  a  slender  pointer  held  in  place  by  a  thumb  nut  and  which 
projects  well  over  the  scale,  o  is  a  handle  by  which  the  bell  is 
raised,  and  p  is  a  U  gauge  screwed  into  the  top  of  the  valve,  d  or 
e,  and  which  serves  to  show  whether  there  is  any  leak  in  the  system 
beyond  this  valve.  It  does  not  connect  with  the  air  chamber, 
save  when  the  valve  is  open;  when  the  latter  is  closed  a  small 
hole  through  it  connects  the  gauge  with  the  meter. 

In  another  form  of  prover  very  commonly  in  use,  the  scale  is 
screwed  to  the  bell  in  line  with  the  air  chamber,  and  the  pointer 
consists  either  of  a  needle  or  of  a  strip  of  metal  about  one  inch 
wide  which  projects  horizontally  from  the  top  edge  of  the  tank. 

Some  of  the  older  forms  of  prover  have  a  circular  scale,  and  the 
motion  of  the  bell  is  transferred  by  suitable  gearing  to  a  hand 
revolving  on  the  scale.  In  many  cases  the  bell  is  not  supported 
from  the  center,  but  a  triangular  chain  reaches  from  hooks  on  the 
edge  of  the  dome  to  the  chain  passing  over  the  wheel.  Certain 
well-equipped  meter  shops  connect  the  valve,  e,  to  a  compressed- 
air  supply;  this  saves  a  great  deal  of  labor  in  raising  the  bell,  but 
there  seems  to  be  danger  that  the  temperature  of  the  air  entering 
the  prover  will  not  be  the  same  as  that  of  the  water  and  meter. 
If  this  difficulty  can  be  overcome,  the  device  will  prove  most  con- 
venient and  satisfactory. 

In  England  the  bell  is  raised  by  a  crank  at  the  side  of  the  tank; 
the  writer  has  never  seen  this  in  the  United  States,  and  he  cannot 
recommend  it,  since  it  requires  more  time  than,  and  just  as  much 
labor  as,  the  method  of  direct  pulling  up  of  the  bell  by  hand.  The 
pressure  gauge  is  not  always  screwed  to  the  valve,  but  occasionally 


2/8 


GAS   AND    GAS   METERS 


to  the  pipe  beyond  the  latter.     Several  of  these  points  are  illus- 
trated in  Fig.  50. 

Provers  are  usually  manufactured  in  two,  three,  five,  six,  ten 
and  twelve-foot  sizes.     For  a  small  company,  and  especially  for 


Fig.  50.     Meter  Prover. 

those  supplying  acetylene,  the  two  or  three-foot  size  will  give 
excellent  satisfaction.  If,  however,  the  company  be  large,  or  if 
it  has  meters  larger  than  a  ten-light  to  be  tested,  the  five  or  ten- 
foot  size  is  to  be  recommended.  A  two-foot  galvanized  iron 


THE  CUBIC  FOOT  AND  METER  PROVER       279 

prover  may  be  purchased  for  $80,  while  the  five-foot  size  of  the 
same  material  costs  $125,  and  the  ten-foot  $200. 

If  the  bell  be  of  copper,  the  five-foot  prover  will  cost  $190,  and 
the  two  and  ten-foot  sizes  will  be  proportionately  expensive.  It  is 
coming  to  be  recognized,  however,  that  a  copper  prover  is  the 
more  economical  in  the  end,  as  it  is  practically  unacted  on  by 
water,  and  the  air  only  forms  a  thin  film  of  oxide  over  the  surface, 
which  serves  to  protect  the  remainder  from  further  attack.  On 
the  other  hand,  waters,  and  especially  those  carrying  certain 
amounts  of  carbonic  acid  and  oxygen  in  solution,  attack  vigorously 
the  zinc  which  forms  the  coating  of  the  galvanized  iron,  and  it  often 
happens  that  the  bell  is  perforated  with  fine  holes  a  few  months 
after  it  is  put  in  service.  This  action  of  the  water  is  greatly  facili- 
tated if  the  galvanizing  is  thin  at  any  point,  since  the  moment  both 
zinc  and  iron  in  contact  with  each  other  are  exposed  to  the  water, 
an  electric  current  is  generated  which  increases  to  a  marked 
extent  the  attack  of  the  water  on  the  metals.  For  this  reason  the 
copper  prover  is  to  be  commended  to  all  companies  for  whom  the 
initial  outlay  is  not  too  serious  a  burden. 

In  setting  up  the  prover,  the  following  directions  may  be  of  aid. 
The  tank  is  to  be  placed  upon  its  legs  and  made  to  stand  level. 
Screw  the  columns  in  position  on  the  rim  of  the  tank,  and  fasten 
the  scale  to  the  column  at  the  left  of  the  air  chamber.  Insert  the 
bell  in  the  tank,  placing  it  so  that  the  rollers  are  opposite  to  and 
engage  with  the  guide  rods  on  the  columns;  the  roller  bearing  the 
pointer  is  to  be  adjacent  to  the  scale.  Place  the  iron  tripod  on 
top  of  the  columns  and  fasten  it  in  position  by  means  of  the  acorns. 
The  end  of  the  tripod  bearing  the  bracket  is  to  be  secured  to 'the 
column  bearing  the  scale. 

The  large  wheel  is  next  inserted  between  the  arms  of  the  bracket, 
its  axis  resting  on  the  anti-friction  rolls  and  the  cycloid  being 
behind  the  large  wheel.  Fasten  the  cord  to  the  end  of  the  cycloid, 
and  attach  the  nickel  weight  to  the  acorn  on  the  other  end  of  the 
cord,  allowing  the  latter  to  rest  in  the  groove  of  the  cycloid. 
Hook  the  chain  on  to  the  bell,  pass  it  over  the  large  wheel,  and 
fasten  the  heavy  iron  weight  to  its  other  end.  Screw  the  pressure 


280  GAS   AND   GAS   METERS 

gauge  into  the  top  of  the  outlet  valve,  and  then,  with  the  circular 
slide  valve  open,  pour  water  into  the  space  between  the  tank  and 
the  inner  dome  until  the  level  of  the  liquid  rises  to  within  about 
two  inches  of  the  top  rim  of  the  tank.  Haul  up  the  bell  by  pulling 
on  the  chain  handle  until  the  pointer  reaches  the  zero  mark,  then 
close  the  slide  valve;  the  prover  is  now  ready  for  use. 

The  prover  should  be  set  up  in  a  well-lighted  room  where  the 
temperature  may  be  maintained  between  60  degrees  and  70  degrees 
throughout  the  year.  It  should  not  be  placed  near  a  radiator, 
hot-water  pipes  or  register,  and  if  it  is  near  a  window  or  door,  care 
must  be  exercised  to  see  that  no  drafts  from  the  latter  strike  it, 
and  that  direct  sunlight  does  not  fall  on  or  near  the  bell  or  tank. 
A  supply  of  cold  water  should  be  handy,  and  some  means  provided 
whereby  hot  water  may  be  readily  secured.  If  the  connection 
with  the  meter  is  to  be  made  through  the  valve  on  the  left,  a  bench 
should  be  placed  on  that  side  to  hold  the  meter. 

Connections  and  rates  should  be  arranged  in  a  drawer  or  on  a 
board  near  by,  and  a  supply  of  washers  of  various  sizes  should  be 
provided.  It  will  be  found  convenient  to  suspend  the  rubber  hose, 
which  connects  the  prover  to  the  meter,  from  a  hook  in  the  ceiling, 
so  that  when  it  is  disconnected  from  the  meter  it  will  remain  hang- 
ing in  the  air  ready  for  the  next  connection,  and  will  not  cramp. 

Two  thermometers  must  be  provided  which  shall  read  the  same 
under  similar  conditions.  One  of  these  should  be  used  only  for 
taking  the  temperature  of  the  air;  the  other  should  be  attached  to 
a  chain  or  string,  whereby  it  may  be  lowered  into  the  water  in  the 
tank.  If  the  air  thermometer  were  used  for  taking  the  temperature 
of  the  water,  it  could  not  again  be  employed  for  readings  in  the  air 
for  some  time,  since  the  evaporation  of  the  moisture  from  the  bulb 
cools  the  mercury,  and  the  record  of  the  instrument  will  be  far  too 
low  until  it  is  again  entirely  dry. 

A  simple  device  is  in  use  in  many  places  to  enable  the  operator 
to  devote  the  time  while  the  meter  is  running  to  some  other  pursuit. 
This  consists  of  a  small  bell  fastened  to  one  of  the  columns  and  a 
strip  of  metal  to  the  contiguous  part  of  the  bell.  When  the  latter 
has  nearly  reached  the  end  of  the  test,  the  bell  rings  automatically 


THE  CUBIC  FOOT  AND  METER  PROVER       28 1 

and  thus  calls  the  tester,  who  may  in  the  meantime  have  been  busy 
in  some  other  part  of  the  room. 

Care  of  the  Prover.  Certain  precautions  must  be  observed  to 
keep  a  prover  in  good  condition.  The  bell  should  never  be  left  in 
the  water  for  any  length  of  time,  especially  if  it  be  a  galvanized-iron 
prover.  The  Canadian  regulations  for  inspectors  require  that  the 
bell  shall  be  raised  completely  out  of  the  water  and  held  so  by  a 
brace  placed  between  the  spokes  of  the  large  wheel.  This  is  not  a 
bad  idea,  and  may  well  be  followed  when  the  prover  is  not  to  be 
used  for  some  days.  A  fresh  coat  of  paint  occasionally  applied  to 
the  interior  of  the  tank  and  to  the  exterior  of  the  bell  and  dome  or 
air  pipe  will  also  greatly  retard  the  injurious  action  of  the  water  on 
the  metallic  surfaces.  The  water  in  the  tank  should  be  changed 
occasionally  as  the  stale  water  becomes  foul  with  dirt,  paint,  iron 
oxide,  etc.  The  scale  should  be  kept  polished,  and  likewise  the 
nickel  work  on  the  valves. 

Considerable  attention  must  be  given  to  the  slide  valve  to  see  that 
it  is  kept  clean  and  well  greased.  Small  particles  of  dirt  and  grit 
settle  on  the  exposed  surfaces  of  this  valve  and  are  caught  and  held 
there  by  the  grease  used  as  lubricant.  If  these  are  not  removed 
they  will  slowly  grind  into  the  smooth  valve  seat  and  cause  a  leak. 
A  cup  is  usually  furnished  with  all  new  provers,  and  this  should  be 
placed  over  the  slide  valve  whenever  the  latter  is  not  in  use.  The 
other  valves  must  also  be  kept  greased,  or  a  leak  will  be  the  result. 
If  the  chain  rusts  badly  it  will  not  run  smoothly  over  the  wheel,  and 
consequently  the  movement  of  the  bell  will  be  erratic. 

The  large  weight  and  the  one  attached  to  the  cycloid  should  never 
be  changed  after  the  prover  has  once  been  tested;  this  is  very  im- 
portant, and  the  reason  therefor  will  be  made  clear  by  a  considera- 
tion of  the  functions  of  these  weights.  The  chain  weight  is  intended 
to  counterbalance  to  a  certain  extent  the  weight  of  the  bell,  leaving, 
however,  enough  excess  to  the  latter  to  maintain  a  pressure  of  1.5 
inches  at  the  outlet  of  the  prover.  But  as  the  bell  is  lowered  into 
the  water,  the  latter  exercises  a  greater  and  greater  buoyant  effect, 
and  therefore  the  chain  weight,  which  might  have  been  adequate 
for  its  purpose  when  the  bell  was  at  its  highest  point,  would  be 


282  GAS  AND   GAS   METERS 

incorrect  when  the  water  had,  so  to  speak,  removed  a  portion  of  the 
weight  from  the  bell.  The  cycloid  weight  is  intended  to  compen- 
sate for  this,  and  is  so  constructed  that  at  every  point  in  the  move- 
ment of  the  bell  the  pressure  exerted  by  the  latter  is  exactly  the 
same.  Now  if  either  of  these  weights  is  altered,  the  pressure  on 
the  gas  or  air  in  the  bell  is  likewise  changed,  with  the  result  that 
the  volume  of  air  or  gas  is  less  or  greater  than  it  would  be  under 
standard  conditions. 

Standardizing  the  Prover.  This  operation  must  be  performed  in 
a  room  saturated  with  moisture  and  where  the  temperature  may  be 
kept  constant  for  at  least  two  hours.  Drafts  must  be  rigorously 
excluded,  and,  on  account  of  the  temperature  qualification,  no 
heating  apparatus  should  be  within  the  room  itself.  For  the  same 
reason  no  gas  should  be  allowed  to  burn  in  the  room  during  the  test, 
and  direct  sunlight  should  be  excluded.  To  saturate  the  room  with 
moisture,  the  floors  and  walls  should  be  kept  wet,  and  blankets 
soaked  in  water  hung  from  wires  throughout  the  room,  and 
especially  in  the  neighborhood  of  the  prover  and  the  cubic  foot. 

The  degree  of  saturation  may  be  determined  by  means  of  a  wet 
and  dry  bulb  thermometer,  or,  if  this  be  not  available,  it  may  be 
roughly  estimated  by  dipping  an  ordinary  thermometer  in  water 
and  then  hanging  it  in  the  air.  If  the  room  is  saturated  with  moist- 
ure, the  mercury  in  this  thermometer  will  not  fall  to  any  extent, 
because  the  air  already  contains  all  the  moisture  which  it  can  hold, 
and  thus  evaporation  from  the  bulb  of  the  thermometer,  which 
would  ordinarily  ensue,  with  consequent  lowering  of  the  mercury 
column,  is  prevented.  The  reasons  for  these  two  precautions  as  to 
temperature  and  saturation  will  become  plain  as  the  description  of 
the  test  proceeds. 

Connect  the  prover  and  cubic  foot  by  means  of  a  piece  of  heavy 
rubber  tubing,  and  test  for  a  leak  by  turning  on  the  prover  valve  and 
then,  after  a  moment,  turning  it  off  and  watching  the  pressure 
gauge  above  the  valve.  If  there  be  a  leak  anywhere  between  this 
valve  and  the  upper  gauge  glass  of  the  cubic  foot,  the  water  in  the 
U  gauge  will  fall.  If  now  the  temperatures  of  water,  room  and 
cubic  foot  be  all  precisely  the  same,  set  the  bell  of  the  prover  so  that 


THE  CUBIC  FOOT  AND  METER  PROVER       283 

the  pointer  rests  exactly  on  the  zero  mark  of  the  scale,  open  the 
prover  valve,  turn  the  upper  three-way  cock  of  the  cubic  foot  so  that 
the  latter  is  cut  off  from  the  small  air-exit  tube  but  is  connected  with 
the  prover.  See  that  the  water  in  the  gauge  glass  is  at  the  standard 
mark  on  the  latter,  and  then  turn  the  outlet  three-way  cock  so  that 
the  water  runs  into  the  lower  tank. 

When  the  water  reaches  the  standard  mark  on  the  lower  gauge 
glass,  close  the  outlet  cock  on  the  cubic  foot  and  scratch  on  the 
prover  scale  the  position  of  the  pointer.  This  will  be  the  loca- 
tion of  the  one-foot  mark.  Pump  the  water  into  the  upper  tank 
of  the  cubic  foot,  turn  the  upper  three-way  cock  so  as  to  connect 
the  cubic  foot  with  the  air  outlet  tube,  open  the  water  cock  and 
allow  the  water  to  run  into  the  copper  tank  until  it  reaches  the 
upper  standard  mark. 

With  the  pointer  of  the  prover  on  the  scratch  at  the  one-foot 
mark,  repeat  the  operation,  and  so  on  until  the  entire  length  of 
the  scale  has  been  marked  in  feet.  Each  foot  may  then  be  pro- 
portionately divided  into  tenths  and  such  other  divisions  as  may 
be  desired. 

The  principle  of  the  operation  is  this :  As  the  water  runs  out  of 
the  copper  tank  it  sucks  over  air  from  the  bell  of  the  prover,  and 
since  this  copper  vessel  holds  exactly  one  cubic  foot  between  the 
two  marks  on  the  gauge  glasses,  if  the  water  is  run  out  for  this 
distance  precisely  one  cubic  foot  of  air  must  have  been  drawn 
over  from  the  bell.  And  now  the  importance  of  the  precau- 
tions regarding  temperature  and  moisture  will  be  apparent;  for 
if  dry  or  unsaturated  air  were  drawn  into  the  bell  of  the  prover, 
it  would  pick  up  moisture  from  the  water  in  the  tank,  and  thus 
would  not  measure  the  same  when  transferred  to  the  cubic 
foot.  In  like  manner,  if  the  temperatures  of  prover  and  cubic 
foot  were  not  the  same,  a  cubic  foot  of  air  from  the  prover 
would  occupy  a  different  volume  when  transferred  to  the  standard 
apparatus. 

The  method  just  described  is  only  one  of  the  two  courses  of 
procedure  followed  to-day.  In  the  other,  weights  are  attached  to 
the  chain  or  placed  on  top  of  the  bell,  until,  with  the  slide  valve 


284  GAS  AND   GAS  METERS 

open,  the  bell  will  remain  in  any  position  in  which  it  is  placed, 
thus  indicating  that  there  will  be  no  pressure  on  its  contents  when 
filled  with  air.  The  remainder  of  the  test  is  conducted  as  above 
described.  This  is  doubtless  the  most  scientific  way  to  test  a 
prover,  since  there  is  no  compression  of  the  air,  and  therefore  no 
possibility  of  making  the  divisions  on  the  scale  too  small  (con- 
sidering only  the  question  of  pressure).  On  the  other  hand,  the 
first  method  tests  the  prover  under  exactly  the  same  conditions 
which  will  prevail  during  a  meter  test,  namely,  with  the  bell  exert- 
ing a  pressure  of  1.5  inches,  and  therefore,  unless  the  results  by 
this  process  vary  materially  from  those  secured  by  the  second 
method,  it  would  seem  to  be  satisfactory  for  practical  purposes. 
A  short  series  of  tests  by  the  writer,  using  both  forms  of  pro- 
cedure, failed  to  reveal  any  appreciable  difference  between  the 
two;  indeed,  the  marks  on  the  scale  were  exactly  the  same  in 
each  case,  so  that  it  would  seem  as  if  the  difference  between  the 
two  processes  were  more  theoretical  than  real. 

In  addition  to  what  has  been  already  said,  one  further  pre- 
caution should  be  noted.  The  bell  should  be  raised  to  its  full 
height  and  maintained  there  for  a  sufficient  time,  before  com- 
mencing a  test,  to  permit  of  its  surface  becoming  thoroughly 
dry.  The  reason  for  this  is  that  the  evaporation  of  moisture 
from  the  outer  surface  would  cause  cooling  of  the  air  content 
and  thus  a  diminution  of  the  volume  of  the  latter.  If,  however, 
the  room  be  thoroughly  saturated  with  moisture,  this  precaution 
loses  much  of  its  importance. 

With  the  older  form  of  water  bottle  the  procedure  is  somewhat 
different.  The  bottle,  after  connection  with  the  prover,  is  hauled 
out  of  the  water  and  allowed  to  drain.  Then  it  is  lowered,  and  as 
soon  as  the  lower  end  is  sealed  by  the  water  in  the  tank,  the  valve 
leading  to  the  prover  is  opened,  and  air  is  forced  from  the  cubic 
foot  into  the  bell  of  the  prover.  Of  course  in  this  case  the 
graduation  of  the  scale  proceeds  from  the  higher  to  the  lower 
marks;  if,  however,  the  scale  be  on  the  bell  itself,  the  zero  mark 
will  be  at  the  bottom,  and  the  calibration  proceeds  in  the  usual 
manner.  With  this  form  of  standard,  the  bell  of  the  prover  must 


THE  CUBIC  FOOT  AND  METER  PROVER       285 

be  exactly  counterbalanced  by  weights  on  the  chain,  and  it  is  not 
advisable  to  test  with  the  1.5  inch  pressure  method. 

The  styles  of  the  cubic  foot  may  now  be  compared.  The 
modern  form  is  very  accurate,  may  be  set  up  out  of  the  way 
against  a  wall,  and  may  be  used  with  either  the  balanced  bell  or 
with  1.5  inches  pressure.  It  is  always  ready  for  use,  and  the  water 
content  is  less  liable  to  fluctuations  in  temperature  than  is  the 
case  with  the  older  form.  On  the  other  hand,  it  is  difficult  to 
clean  the  tanks,  which  may  become  fouled  through  the  action  of 
water  on  the  metallic  surfaces  and  through  deposition  of  a  min- 
eral or  organic  sediment  from  the  water  itself.  There  are  a  great 
many  joints  to  be  watched  and  lubricated,  and  therefore  many 
possibilities  of  a  leak.  The  pumping  of  the  water  from  the  lower 
to  the  higher  tank  is  a  tedious  process,  and  the  entire  test 
requires  a  much  longer  time  than  does  the  use  of  the  water 
bottle.  Finally,  the  apparatus  is  very  heavy  and  in  no  sense 
portable. 

The  older  water  bottle  operates  more  rapidly  and  nearly  as 
accurately  as  the  above;  it  is  portable,  simple  and  easily  cleaned. 
There  are  but  few  joints  to  be  watched,  and  the  labor  involved 
in  a  test  is  comparatively  small.  Its  accuracy  is  somewhat  dimin- 
ished by  the  fact  that  the  bottle  during  each  foot  run  becomes 
submerged  in  the  water,  and  on  raising  it  there  is  an  evaporation 
from  the  surface  which  tends  to  diminish  the  volume  of  air 
within. 

The  water  is  exposed  to  the  air,  and  is  thus  liable  to  change  its 
temperature  frequently  during  the  test.  Moreover,  in  draining, 
the  water  runs  in  a  comparatively  small  stream  through  the  air, 
and  thus  becomes  cooled.  The  end-point  is  not  quite  as  sharp  and 
as  satisfactory  as  with  the  more  modern  instrument,  and  unless 
care  is  used,  an  error  is  liable  to  be  introduced  at  this  point. 

Again,  in  testing  with  this  form  of  standard,  the  bell  starts  from 
the  bottom  of  the  tank  and  works  upward.  When  the  portions 
which  have  been  submerged  come  in  contact  with  the  air,  the 
evaporation  of  water  from  the  metallic  surface  cools  the  contents 
of  the  bell,  and  thus  a  change  in  volume  may  ensue. 


286  GAS   AND   GAS   METERS 

On  the  whole,  it  is  probable  that  the  modern  cubic  foot  is  the 
more  accurate  and  scientific  instrument,  but  there  is  little  doubt 
that,  with  careful  manipulation  and  in  experienced  hands,  the 
water  bottle  will  furnish  results  which  are  more  than  sufficiently 
accurate  for  practical  purposes. 


CHAPTER  II. 
TESTING  OF  METERS. 

Dry  Meters.  In  the  testing  of  meters  the  most  important  factor 
to  be  considered  is  that  of  temperature.  This  point  has  been 
dwelt  upon  at  some  length  in  connection  with  the  standardization 
of  provers,  and  as  the  same  general  principle  applies  to  meter  test- 
ing, the  argument  will  not  be  repeated. 

Meters  must  stand  in  the  proving  room  for  a  sufficient  length  of 
time  to  permit  them  to  acquire  the  room  temperature.  This 
period  will  vary  with  the  seasons  and  the  conditions  of  the  meter 
shop,  but  in  general  it  is  safe  to  say  that  at  least  twelve  hours  should 
be  allowed,  although  this  may  be  materially  lessened  during  the 
summer  months.  The  meters  should  be  placed  upon  a  wooden 
shelf  or  platform  raised  from  the  floor,  since  the  cold  drafts  in  a 
room  follow  the  lower  levels,  and  the  floor  itself  is  generally  much 
colder  than  the  remainder  of  the  room. 

If  ideal  conditions  could  be  secured,  the  temperature  of  this 
room  would  be  maintained  at  all  times  at  62°  F.,  since  that  is  the 
temperature  at  which  the  standard  cubic  foot  was  calibrated. 
This  is,  of  course,  impossible,  and  is  not  essential  for  practical 
work.  The  thing  which  is  absolutely  indispensable,  however,  is 
that  the  temperature  of  the  air  in  the  room  and  in  the  prover,  the 
water  in  the  latter  and  the  meter  itself,  shall  be  all  within  2°  F.  of 
each  other.  It  is,  of  course,  desirable  to  have  them  even  closer 
than  this,  but  a  difference  of  2  degrees  means  only  about  one-half 
per  cent  error  in  the  result,  and  from  the  nature  of  the  meter  it  is 
generally  conceded  that  it  is  practically  impossible  to  regularly 
secure  results  which  check  within  much  less  than  this  figure. 

If  the  water  in  the  prover  be  colder  than  the  air,  its  temperature 
may  be  raised  by  the  addition  of  hot  water  or  by  the  injection  of 
steam.  Whichever  of  these  methods  is  followed,  the  contents  of 

287 


288  GAS  AND   GAS   METERS 

the  tank  must  be  thoroughly  mixed  before  again  taking  its  tem- 
perature. 

When  all  is  in  readiness  for  the  test,  the  meter  is  placed  upon  the 
bench  and  its  inlet  connected  to  the  prover  by  the  use  of  the  proper 
connecting  union,  which  is  wired  into  the  end  of  the  rubber  hose. 
This  union  must  be  provided  with  a  clean,  sound  washer  which 
has  not  been  ridged  or  cut.  Do  not  screw  on  the  union  so  tightly 
as  to  spoil  the  washer;  the  writer  has  seen  so  many  connections 
made  with  a  large  Stilson  wrench  and  the  full  power  of  two  brawny 
arms  that  he  has  come  to  the  conclusion  that  more  leaks  are  caused, 
in  the  testing  of  a  meter,  by  too  much  tightening  than  by  too  little 
tightening  of  the  inlet  union. 

The  next  step  is  to  test  for  a  leak  in  the  meter  or  connections. 
Open  the  prover  valve,  and  as  soon  as  it  is  seen  that  air  is  issuing 
freely  from  the  meter  outlet,  place  the  palm  of  the  hand  tightly 
over  the  latter  and  turn  off  the  prover  valve.  Watch  the  pressure 
gauge,  and  if  the  water  falls  more  than  0.2  inch  it  is  evidence  of  a 
leak  between  the  valve  and  the  outlet  of  the  meter,  and  this  must 
be  stopped  before  proceeding.  There  is  a  very  good  reason  for 
allowing  air  to  pass  through  the  meter  before  closing  the  outlet 
with  the  hand.  It  frequently  happens  that  the  meter  sticks  at 
first  and  may  not  pass  gas  at  all.  In  such  a  case,  if  the  hand  were 
placed  over  the  outlet  at  the  start,  the  pressure  gauge  would 
indicate  no  leak,  although  such  might  exist. 

If  no  leak  be  found,  open  the  prover  valve  and  allow  a  quantity 
of  air  to  pass  through  the  meter,  the  amount  varying  with  the  size 
of  the  latter.  With  a  3 -light  meter,  from  i  to  2  feet  is  generally 
considered  to  be  sufficient,  and  it  is  probable  that  one-half  foot 
will  answer  all  requirements.  This  air  is  passed  to  allow  the 
meter  to  assume  its  normal  rate  of  action  before  commencing  the 
test,  and  to  be  certain  that  nothing  but  air  of  the  room  temperature 
fills  the  diaphragms  when  the  test  begins.  For  the  larger  sizes  of 
meters  it  is  obvious  that  a  proportionately  larger  amount  of  air 
must  be  passed  to  accomplish  this. 

The  testing  circle  of  the  meter  is  the  small  one  in  the  center  of 
the  upper  portion  of  the  dial.  For  the  3  and  5-light  sizes  this  is 


TESTING    OF   METERS 


289 


Fig.  51.     Meter  Prover  and  Meter  Connected  for  Test 


2QO  GAS   AND   GAS   METERS 

usually  a  2-foot  circle,  although  with  meters  employed  with  acety- 
lene it  may  be  smaller  than  this;  indeed,  the  writer  has  seen  an 
So-light  meter  with  a  i-foot  testing  circle.  This  circle  is  divided 
into  fractions  of  a  foot  by  small  marks  or  dots  on  its  circum- 
ference. As  the  hand  approaches  one  of  these  divisions  on  the  side 
of  the  circle,  the  rate  or  speed  union  is  to  be  placed  on  the  meter 
outlet,  and  when  the  hand  exactly  covers  the  desired  mark,  the 
prover  valve  is  closed. 

Authorities  differ  greatly  as  to  whether  the  test  should  be  com- 
menced with  the  hand  at  the  top  of  the  dial,  at  the  bottom,  on  the 
down  stroke  or  on  the  up  stroke.  If  the  mechanism  of  the  meter 
were  perfect,  the  starting  point  would  probably  have  little  or  no 
influence  on  the  result  of  the  test;  but  various  considerations  of 
back-lash,  lost  motion,  etc.,  have  led  to  the  belief  that  the  error  is 
less  if  the  meter  be  started  from  a  side  point  than  if  the  top  or  bottom 
is  selected.  With  regard  to  which  side  should  be  chosen,  opinions 
of  experts  seem  to  be  evenly  divided,  and  therefore  neither  side  is 
particularly  recommended,  it  being  the  writer's  belief  that  the 
results  will  not  be  seriously  influenced,  from  a  practical  standpoint, 
by  the  selection  of  either  the  down  or  the  up  stroke. 

The  meter  may  be  tested  with  open  outlet  and  approximate 
results  secured,  but  the  generally  accepted  legal  test  is  made  with 
the  rate  on  the  outlet.  Rates,  or,  as  they  are  sometimes  called, 
speed  unions,  are  made  in  two  styles.  In  one,  a  small  threaded  cap 
is  perforated  with  a  hole  of  the  desired  size,  while  the  other  consists 
of  a  small  brass  cylinder  with  a  shoulder  at  the  bottom,  the  top  being 
closed  save  for  the  perforation.  The  size  of  this  aperture  varies  for 
different  sizes  of  meters,  but  all  have  this  common  property :  with  a 
pressure  of  i  J  inches  on  the  inlet  and  the  rate  screwed  on  the  outlet, 
the  meter  should  pass  gas  at  the  rate  of  as  many  tenths  of  a  cubic 
foot  per  minute  as  the  meter  has  lights.  In  other  words,  a  3-light 
rate  should  pass  0.3  cubic  foot  per  minute,  or  18  feet  per  hour.  With 
natural  gas  meters,  which  are  classified  by  sizes  and  not  by  lights, 
the  custom  is  to  use  the  same  rate  as  would  be  employed  with  an 
artificial  gas  meter  of  the  same  capacity. 

The  theory  of  the  rate  is  that  the  meter  should  be  tested  under 


TESTING    OF   METERS  29 1 

conditions  which  at  least  approximate  those  which  will  be  met  in 
service.  It  is  therefore  assumed  that  a  5-light  meter,  for  example, 
will  on  an  average  be  called  upon  to  supply  30  feet  per  hour  or  less, 
although  its  capacity  is  over  twice  this  amount.  The  assumption 
doubtless  was  fair  in  the  earlier  days  of  the  gas  industry,  when  cook- 
ing and  heating  appliances  were  practically  unknown ;  but  to-day, 
when  the  gas  used  for  fuel  purposes  forms  nearly  50  per  cent  of  the 
total  output,  it  is  somewhat  questionable  whether  the  rate  test  is  a 
reasonable  criterion  of  the  action  of  the  meter  when  in  service.  As 
it  is  in  many  cases,  however,  a  legal  requirement,  it  will  probably 
continue  in  use  for  some  time  to  come. 

It  will  be  noticed  that  the  rate  is  to  be  placed  in  position  on  the 
meter  during  the  preliminary  run  and  before  the  hand  has  reached 
the  starting  point  of  the  test.  The  purpose  of  this  is  to  see  that  the 
meter  acquires  its  moderated  speed  before  commencing  the  actual 
test.  This  may  appear  to  be  a  small  matter,  and  indeed,  it  is  often 
ignored;  but  it  should  be  borne  in  mind  that  accuracy  in  this,  as 
well  as  in  every  branch  of  science  and  business,  is  secured  only  by 
strict  attention  to  numerous  small  precautions,  each  of  which  in 
itself  would  seem  hardly  worthy  of  recognition. 

The  bell  of  the  prover  is  now  raised  until  the  pointer  is  a  trifle 
above  the  zero  mark  on  the  scale.  Then  by  careful  manipulation 
of  the  unemployed  outlet  valve,  the  bell  is  allowed  to  sink  slowly 
until  the  pointer  is  exactly  on  zero.  Now  open  the  valve  leading 
to  the  meter  and  allow  sufficient  air  to  pass  through  the  latter  to 
cause  one  complete  revolution  of  the  test  hand.  When  this  hand 
exactly  reaches  its  starting  point  the  prover  valve  is  closed,  and  the 
reading  on  the  scale  noted.  Results  are  expressed  in  per  cent  and 
fractions  of  a  per  cent;  a  fast  percentage  is  designated  as  plus,  and 
a  slow  one,  as  minus.  Check  tests  of  the  same  meter  should  be  run 
from  different  points  on  the  dial  and  should  agree  within  0.5  per 
cent. 

To  test  meters  having  a  testing  circle  of  10  feet  or  more  on  a  5 -foot 
prover,  the  operation  is  commenced  exactly  as  already  described. 
When  the  prover  reaches  the  5-foot  mark,  it  is  shut  off,  drawn  up  to 
zero,  and  the  operation  repeated  as  many  times  as  necessary.  On 


2Q2  GAS   AND   GAS   METERS 

the  run  immediately  preceding  the  end,  however,  the  prover  is  not 
stopped  at  exactly  the  5-foot  mark,  but  wherever  it  may  be  when  the 
meter  hand  again  reaches  its  starting  point. 

In  testing  meters  which  have  just  been  removed  from  service,  it 
will  often  be  found  that  the  meter  will  run  faster  and  faster  as  test 
after  test  is  made.  The  cause  of  this  is  simple:  the  passage  of  gas 
through  the  meter  has  left  in  the  diaphragms  certain  light  and  vola- 
tile oils.  When  the  air  from  the  prover  strikes  these,  the  tendency 
is  for  them  to  evaporate,  and  in  so  doing,  the  diaphragm  gradually 
dries  out  and  shrinks.  As  the  capacity  of  the  diaphragm  decreases, 
the  register  increases,  because  the  latter  makes  a  certain  movement 
for  each  pulsation  of  the  diaphragm,  which  in  turn  is  caused  by  the 
passage  of  a  definite  amount  of  gas.  If  now  a  smaller  amount  of 
gas  produces  the  same  pulsation  and  consequently  the  same  move- 
ment on  the  dial,  it  is  clear  that  the  meter  is  registering  more  gas 
than  it  passes,  and  consequently  is  fast.  In  the  case  of  meters 
which  behave  in  this  manner  and  for  the  above-mentioned  cause,  it 
would  seem  that  the  first  test  made  represented  most  nearly  the 
registration  of  the  meter  while  in  service,  and  therefore  is  the  one  to 
be  accepted  and  reported  if  the  meter  belongs  to  the  "complaint" 
class. 

Another  difficulty  not  infrequently  met  in  the  case  of  meters 
recently  removed  from  service,  is  to  have  the  valves  drag  after  air 
has  been  passed  through  them.  This  is  caused  by  the  fact  that 
the  valves  may  hold  a  certain  amount  of  condensate  from  the 
gas,  which  will  not  affect  the  action  of  the  meter  as  long  as  gas  is 
passing  through  it.  As  soon,  however,  as  air  comes  in  contact 
with  this  condensate,  a  chemical  change  sets  in,  and  the  deposit 
hardens,  and  so  hinders  the  working  of  the  valves. 

In  many  cases  the  test  of  a  meter  is  made  with  gas  instead  of 
air,  and  this  will  serve  to  obviate  both  of  the  above-mentioned 
difficulties.  Indeed,  where  it  is  convenient,  it  is  well  to  keep 
one  prover  filled  with  gas  and  to  test  all  complaint  meters  thereon. 
The  general  practice  of  testing  all  meters  with  gas  is  not  to  be 
recommended.  The  gas  issuing  from  the  meter  must  either  be 
led  outside  of  the  building  or  be  burned  at  the  outlet.  In  the 


TESTING   OF   METERS  2Q3 

first  case  it  is  liable  to  become  a  nuisance,  and  in  the  second  it 
serves  to  rapidly  change  the  temperature  of  the  room.  Air  costs 
nothing,  and  may  readily  be  obtained  of  the  room  temperature; 
gas  is,  relatively  speaking,  expensive,  and  coming  from  the  holder 
or  mains,  it  is  liable  to  be  of  very  different  temperature  from  the 
water  in  the  prover  and  from  the  meter.  Gas  gives  no  more 
satisfactory  results  (except  in  the  cases  above  mentioned)  than 
does  air,  and  has  the  final  disadvantage  of  being  dangerous. 
This  may  seem  absurd,  but  the  writer  has  seen  the  entire  top  of 
a  heavy  iron  meter  blown  out  by  carelessness  in  testing  with  gas, 
and  only  by  the  best  of  fortune  did  the  tester  escape  serious 
bodily  injury. 

There  are  two  methods  in  common  use  to-day  for  calculating 
the  percentage  error  of  the  meter,  and  as  there  has  been  con- 
siderable controversy  over  these,  they  will  be  discussed  some- 
what in  detail.  The  first,  which  will  be  called  method  A  for 
brevity,  consists  in  dividing  the  difference  between  the  readings 
of  the  meter  and  prover,  multiplied  by  100,  by  the  prover  read- 
ing; the  second,  or  method  B,  divides  the  same  figure  by  the 
reading  of  the  meter.  To  illustrate,  assume  that  the  meter  read 
2.0  feet  and  the  prover  1.96  feet.  By  method  A  the  percentage 
error  of  the  meter  would  be 

(s.oo  -  1.96)  X  ioo>  or  2>04  pe 
1.96 

By  method  B  the  calculation  would  be 

(2.OO    —    I. O6)    X    IOO  ,     r 

1—2 =  2.00  per  cent  fast. 

2.00 

In  practice  these  calculations  are  seldom  employed,  the  percent- 
age by  method  A  being  found  from  a  table  which  will  be  given  in 
the  appendix,  and  by  method  B  being  read  direct  from  the  prover 
scale,  as  will  be  explained  later. 

Reduced  to  simple  terms,  the  difference  between  the  two 
methods  is  this:  "A"  determines  what  percentage  of  the  gas 
passing,  registers;  "B"  determines  what  percentage  of  the  gas 
registered,  actually  passes  the  meter.  "A"  takes  the  volume  of 


294  GAS   AND   GAS   METERS 

gas  passing  as  the  central  point  or  basis  of  the  calculation;  "B" 
accepts  the  register  of  the  meter  as  the  basis.  Now  it  would 
seem  indisputable  that  both  of  these  methods  are  correct,  if  we 
assume  the  bases  of  calculation  as  given  above.  This  may  seem 
strange  at  first  in  view  of  the  illustration  recently  quoted,  wherein 
the  meter  was  found  to  be  2.04  per  cent  fast  by  one  method  and 
2  per  cent  by  the  other.  If,  however,  the  base  of  the  calculation 
is  remembered,  these  results  are  in  no  wise  contradictory  or  dis- 
cordant. By  method  A  it  is  seen  that  the  meter  registered  102.4 
per  cent  of  the  gas  which  it  actually  passed,  which  was  1.96  feet, 
and  102.4  per  cent  of  1.96  is  2  feet,  the  amount  which  the  meter 
registered  in  the  test.  By  method  B,  it  is  stated  that  the  meter 
passed  only  98  per  cent  of  what  the  register  showed,  and  98  per 
cent  of  2  feet  gives  us  1.96  feet,  the  quantity  of  gas  passed  as 
shown  by  the  prover  reading. 

For  method  A,  it  is  urged  that  the  reading  of  the  prover,  which 
is  authoritative,  is  accepted  as  the  standard,  but  so  it  is  with 
method  B,  that  is,  the  reading  of  the  prover  is  accepted  as  abso- 
lutely correct,  but  the  register  of  the  meter  is  the  central  thought 
and  is  taken  as  the  total,  or  100  per  cent.  This  seems  just  for 
two  reasons:  First,  the  register  itself  is  rarely  in  error,  the  fault 
almost  always  lying  with  the  valves  or  diaphragms;  second,  the 
register  is  the  only  visible  means  which  the  consumer  possesses  of 
ascertaining  the  action  of  his  meter.  As  a  rule,  the  vital  point 
of  interest  to  both  consumer  and  company  is  not  the  amount  of 
gas  which  passes  the  meter,  but  the  quantity  which  is  to  be  paid 
for,  and  this  is  necessarily  the  amount  shown  by  the  dial. 

Moreover,  one  statement  of  percentage  by  method  B  answers 
all  questions,  and  this  is  not  true  of  method  A.  For  instance,  a 
certain  consumer  was  informed  that  his  meter  was  10  per  cent 
fast  (this  percentage  being  reached  by  method  B),  and  he  wrote 
to  the  Public  Service  Commission  of  the  Second  District,  New 
York,  to  know  what  rebate  he  might  expect.  The  answer  was 
simplicity  itself,  10  cents  on  each  dollar  which  he  had  paid. 
Compare  this  with  a  similar  case  where  the  percentage  was  deter- 
mined by  method  A.  Another  meter  was  tested  in  New  York  and 


TESTING    OF   METERS  295 

reported  to  the  consumer  as  42  per  cent  fast.  The  attorneys  for 
complainant  took  this  report  to  the  company  and  were  informed 
that  a  rebate  of  42  per  cent  could  not  be  granted,  but  that  the 
correct  percentage  on  which  to  figure  said  rebate  was  the  ratio  of 
42  to  142,  or  29.6  per  cent,  this  latter  figure  being  exactly  the  one 
which  would  have  been  reached  in  the  first  place  by  method  B. 

In  this  connection  the  following  paragraph  quoted  from  the 
report  of  the  General  Inspector  of  the  company  (the  latter,  by  the 
way,  one  of  the  largest  in  the  world)  is  very  pertinent:  "  As  indicated, 
the  test  of  the  meter  showed  that  it  was  recording  with  an  accuracy 
of  142  per  cent.  This  does  not  mean,  permit  me  to  suggest,  that 
the  meter  was  42  per  cent  fast,  but  rather  approximately  30  per 
cent.  The  meter  record  should  be  100  per  cent;  the  actual  record 
was  142  per  cent;  .  .  .  the  percentage  of  the  overcharge,  it  will  be 
apparent,  is  the  ratio  of  42  to  142,  which  you  will  notice  is  much 
less  than  42  per  cent.  The  exact  result  is  reached  by  dividing  42 
by  142,  which  is  almost  exactly  29.6  per  cent."  In  replying  to 
the  attorneys  for  the  complainant,  and  referring  to  the  above 
paragraph,  the  commission  to  which  this  matter  was  referred, 
says:  "  The  contention  of  the  .  .  .  company  is  therefore 
correct." 

Certain  mathematical  considerations  likewise  seem  to  point  to 
method  B  as  the  most  advisable  one  to  adopt.  According  to 
method  A,  it  is  mathematically  impossible  for  a  meter  to  be 
infinitely  slow,  namely,  to  pass  gas  forever  without  registering  at 
all.  This  will  be  clear  if  we  remember  that  the  formula  for  cal- 
culating percentage  by  this  method  is  "difference  of  prover  and 
meter  divided  by  prover."  In  order  to  make  this  quotient  infinity, 
it  is  necessary  that  the  divisor  should  be  zero.  But  a  meter  cannot 
be  found  slow  unless  the  prover  has  passed  more  gas  than  the 
meter;  consequently  the  reading  of  the  prover  cannot  be  zero,  and 
the  quotient  cannot  be  infinity.  Now  with  method  B,  the  reading 
of  the  meter  is  the  divisor,  and  this  may  be,  and  frequently  is,  zero, 
thus  giving  a  quotient  of  infinity.  It  is  a  matter  of  common  knowl- 
edge and  occurrence  that,  through  leaky  diaphragms  or  other 
causes,  a  meter  may  pass  gas  without  registering,  and  such  a 


296  GAS   AND   GAS   METERS 

meter  is  clearly  infinitely  slow;  this  fact,  then,  is  brought  out  by 
method  B,  and  not  by  method  A. 

Again,  by  method  A,  it  is  mathematically  possible  to  have  a 
meter  infinitely  fast,  that  is,  to  register  gas  forever  without  passing 
anything.  This  conclusion  is  reached  in  the  following  manner: 
If  the  meter  registers  2  feet  and  the  prover  i  foot,  the  meter  is  100 
per  cent  fast.  If  the  prover  reads  but  0.5  foot,  the  percentage  is 
300  fast;  if  it  reads  o.i  foot,  the  percentage  is  1900  fast;  if  it  reads 
o.oi  foot,  the  percentage  is  19,000  fast,  and  so  on.  Pushing  this 
to  its  mathematical  conclusion,  we  reach  a  point  where  the  prover 
reads  zero  and  the  meter  is  infinitely  fast.  An  infinitely  fast  meter 
would  be  a  violation  of  one  of  the  first  principles  of  physics,  since 
we  would  then  have  motion  without  the  expenditure  of  energy. 
With  method  B,  no  meter  can  ever  be  found  to  be  infinitely  fast, 
because  the  divisor  of  the  fraction  above  mentioned  is  the  reading 
of  the  meter,  and  this,  it  is  self-evident,  can  never  be  zero  with  a 
fast  meter. 

One  more  point  of  evidence  in  favor  of  method  B  is  worthy  of 
note.  The  vast  majority  of  meter  provers  have  their  scales  divided, 
in  the  vicinity  of  the  2,  4,  5  and  lo-foot  marks,  so  as  to  enable  one 
to  read  off  the  percentage  error  of  the  meter  direct,  if  method  B 
is  used.  Such  graduation  is  purposely  so  made  by  the  manu- 
facturers with  exactly  that  end  in  view.  This  saves  a  great  deal 
of  time  and  labor,  and  it  would  seem  evident  that  this  action  on 
the  part  of  the  manufacturers  indicates  their  belief  that  method  B 
is  at  least  as  satisfactory  as  method  A.  The  divisions  at  the 
2-foot  mark  are  0.02  foot;  at  the  4-foot  mark  they  are  0.04  foot,  at 
the  5-foot  mark,  0.05,  and  at  the  lo-foot  mark  o.i  foot,  thus  in 
each  case  being  one  one-hundredth,  or  i  per  cent,  of  the  total 
length  of  the  scale  from  zero  to  that  point. 

Let  it  be  distinctly  understood  that  the  writer  is  not  endeavoring 
to  prove  that  method  A  is  incorrect;  on  the  contrary,  it  is  his  firm 
belief  that  both  methods  are  correct,  but  that  "B"  involves  less 
labor,  is  more  easily  comprehensible,  serves  better  to  explain  cer- 
tain facts  connected  with  meters  (that  they  may  be  infinitely  slow, 
for  instance),  is  less  liable  to  give  rise  to  difficulties  with  consumers, 


TESTING   OF   METERS  297 

and  is  in  general  better  suited  to  meter  work.  It  is  realized  that 
"A"  is  upheld  by  many  eminent  authorities  and  is  undoubtedly 
scientifically  correct;  method  B  has,  however,  equally  eminent 
advocates,  and  the  mathematical  deductions  above  given  have 
been  confirmed  by  several  of  the  best  authorities  in  the  United 
States. 

While,  as  has  been  said,  the  temperatures  of  the  room,  the  meter 
and  the  prover  should  all  be  within  2  degrees  of  each  other,  it 
occasionally  happens  that  the  inspector  desires  to  make  a  correc- 
tion for  variations  in  temperature.  For  this,  Abady  gives  the 
following  rule:  "  Multiply  the  number  of  cubic  feet  and  parts 
delivered  from  the  holder  by  the  number  of  degrees  of  difference 
in  temperature  and  by  0.0025,  and,  (a)  if  tne  gas  from  the  meter 
be  higher  in  temperature,  add  the  product  to  the  quantity  indi- 
cated by  the  gas  holder;  (b)  if  the  gas  be  of  lower  temperature  at 
the  -outlet  of  the  meter,  subtract  the  product  from  the  gas  holder 
reading." 

Wet  Meters.  In  testing  a  wet  meter,  such  as  is  used  with  a 
photometer,  a  somewhat  different  procedure  is  followed.  The 
meter  is  first  very  accurately  leveled  and  then  filled  with  water  of 
the  room  temperature  up  to  a  certain  chosen  mark  on  the  gauge 
glass.  In  this  test  the  temperatures  of  the  room  and  prover  should 
be  exactly  the  same;  the  wet  meter  is  intended  for  very  accurate 
work,  and  no  allowance  of  2  degrees,  or  even  0.5  degree,  can  be 
made.  The  prover  is  connected  to  the  meter  inlet  and  air  passed 
through  the  meter  at  the  rate  of  6  feet  per  hour  for  some  time. 
To  secure  this  rate  the  writer  uses  a  6-foot  lava  tip  inserted  in  a 
perforated  cork,  the  latter  being  placed  in  the  outlet  of  the  meter. 
Shut  off  the  prover  when  the  meter  hand  reaches  zero,  set  the 
prover  on  zero,  and  run  2  feet  of  air  through  the  meter.  If  the 
latter  is  found  to  be  slow,  add  water  and  repeat  the  test.  The 
amount  of  water  to  be  added  can  only  be  roughly  stated ;  a  differ- 
ence of  one-sixteenth  inch  in  the  height  of  the  water  in  the  gauge 
glass  is  supposed,  with  a  6-foot  photometer  meter,  to  make  a  dif- 
ference of  about  i  per  cent  in  the  registration  of  the  meter,  but  this 
clearly  will  not  be  the  same  with  different  meters,  varying  sizes  of 


298  GAS    AND   GAS   METERS 

the  gauge  glass,  etc.  The  tests  are  continued  until  the  readings 
of  the  meter  and  prover  exactly  agree.  Then  the  meter  is  dis- 
connected, the  rate  removed,  and  the  valve  above  the  water  glass 
opened. 

Now,  with  the  meter  perfectly  level,  make  a  scratch  on  the  glass 
at  the  lowest  point  touched  by  the  meniscus  of  the  water  in  the 
gauge.  If  no  alterations  are  made  to  the  meter,  this  mark  will 
remain  accurate  for  a  long  time,  as  there  are  no  diaphragms  or 
valves  to  the  wet  meter  to  change  or  become  clogged.  It  should 
never  be  forgotten,  however,  that  the  water  level  must  be  adjusted 
every  time  that  the  meter  is  used,  and  always  with  the  inlet  and 
outlet  open  to  the  air,  or,  in  other  words,  with  absolutely  no  pressure 
on  the  meter. 

For  the  sake  of  increased  accuracy,  the  small  wet  meter  used  with 
the  calorimeter,  the  o-light  dry  meter  and  the  special  photometer 
meter  employed  by  the  writer  are  always  tested  against  a  standard- 
ized wet  meter,  and  with  gas  from  the  city  mains.  The  standard 
meter  is  permanently  set  up  on  a  bench,  and  its  outlet  is  connected 
with  an  iron  pipe,  on  which  are  several  connections  for  rubber  tub- 
ing. The  meter  to  be  tested  is  connected  to  one  of  these,  and  after 
the  whole  system  is  full  of  gas,  the  latter  is  shut  off  and  the  readings 
of  both  meters  recorded.  A  definite  amount  of  gas  is  then  passed, 
at  a  rate  approximating  that  at  which  the  meter  under  test  will 
generally  be  used,  and  again  the  readings  of  both  dials  are  noted. 
It  is  then  a  simple  matter  of  arithmetic  to  figure  the  percentage 
error  of  the  meter. 

In  proving  meters  with  the  tops  off,  or  open-top  meters,  as  they 
are  called,  the  dial  is  not  used,  as  more  accurate  results  can  be 
secured  by  the  use  of  the  tangent  as  an  indicator.  Set  this  at  a 
chosen  point,  and,  starting  the  prover  at  zero,  run  2  feet  of  air 
through  the  meter  and  count  the  number  of  revolutions  of  the  tan- 
gent. If,  when  the  prover  shows  2  feet,  the  position  of  the  tangent 
is  the  same  as  at  the  beginning  of  the  test,  and  if  the  number  of 
revolutions  is  correct  for  the  size  of  meter  under  examination,  no 
further  adjustment  is  necessary.  If,  however,  the  meter  is  fast, 
loosen  the  nut  on  the  tangent  and  turn  it  outward;  this  causes  the 


TESTING   OF   METERS  299 

flag  arms  to  make  a  longer  circuit,  and  consequently  the  meter 
passes  more  gas  for  the  same  number  of  revolutions.  The  number 
of  such  revolutions  which  a  meter  will  make  in  passing  2  feet, 
depends  on  the  size  of  the  meter  and,  somewhat,  on  the  type.  Thus, 
a  3 -light  meter  of  American  manufacture  will  make  18  revolutions, 
and  a  5-light,  12  revolutions,  while  there  is  a  3-light  meter  which 
makes  but  16.  In  the  appendix  will  be  found  a  table  giving  the 
capacities  of  some  of  the  commoner  types  and  sizes  of  meters. 

In  general,  laws  regarding  the  accuracy  of  gas  meters  require 
that  they  shall  not  be  more  than  2  per  cent  in  error,  although  in 
Great  Britain  3  per  cent  is  allowed  if  the  error  be  in  favor  of  the 
consumer,  while  in  St.  Louis,  Mo.,  the  meters  are  required  to  be 
within  i  per  cent  of  theoretical  accuracy.  Considering  these  fairly 
uniform  regulations,  it  seems  just  to  compare  the  results  of  meter 
tests  from  various  localities.  In  view  of  the  general  idea  of  the  con- 
sumer, that  most  meters  are  fast,  and  in  order  to  supply  figures  with 
which  such  statements  may  be  met,  the  following  statistics  of  recent 
date  may  be  of  value. 

During  the  year  1907,  80,703  meters  were  subjected  to  regular 
inspection  in  London.  Of  this  number  78,739,  or  97.6  per  cent, 
were  correct,  while  of  the  incorrect  meters,  only  401,  or  0.5  per  cent 
of  the  total  number,  were,  registering  against  the  consumer.  Out 
of  86,025  meters  tested  in  Edinburgh  in  the  year  ending  May  15, 
1908,  770,  or  nine-tenths  of  i  per  cent,  were  incorrect,  and  the 
remaining  99.1  per  cent  were  correct  within  legal  limits.  In  Can- 
ada, during  the  year  1906-1907,  29,154  meters  were  tested,  and  only 
58,  or  0.2  per  cent,  were  incorrect  to  the  prejudice  of  the  consumer, 
while  99.5  per  cent  were  correct.  The  Massachusetts  State  Inspec- 
tor reports  58,676  meters  tested  during  1908;  of  these  about  99.8 
per  cent  were  correct,  and  0.2  per  cent  were  incorrect.  In  New 
York  State,  outside  of  New  York  City,  the  Public  Service  Com- 
mission tested,  during  1908,  103,236  meters.  Of  these,  99,065,  or 
96.0  per  cent, were  correct;  2045,  or  2.0  per  cent, were  fast;  and  1675, 
or  1.6  percent,  were  slow.  The  average  error  of  the  fast  meters 
was  4.0  per  cent,  and  of  the  slow  meters,  5.6  per  cent.  Evidence 
such  as  this  could  be  multiplied  indefinitely  to  prove  that  the  vast 


30O  GAS   AND    GAS   METERS 

majority  of  gas  meters  in  use  to-day  were  correct  when  they  were 
put  in  service,  and  while  with  "complaints"  the  number  of  fast 
meters  is  naturally  much  greater  than  with  regular  meters,  the 
average  percentage  error  of  such  meters,  if  taken  over  a  considerable 
period  of  time,  will  rarely  exceed  5.5  per  cent,  and  the  burden  of 
evidence  seems  to  prove  conclusively  that  the  gas  company  loses 
vastly  more  by  its  slow  meters  than  it  gains  by  those  which  are  fast. 


APPENDIX. 


TABLE    I.  —  ATOMIC    WEIGHTS. 


Name. 

Sym- 
bol. 

O  =  i6. 

H  =  i. 

Name. 

Sym- 
bol. 

O  =  i6. 

H  =  i. 

Aluminium 

Al 

27    I 

26  o 

Mercury 

Hff 

200  o 

108  c 

Antimony  
Arsenic  

Sb 

As 

120.  2 
7C    o 

iiQ-3 

74   4 

Molybdenum  .  . 
Nickel 

Mo 

Ni 

96.  o 

s8  7 

95-3 
t;8  3 

Barium  

Ba 

137   4 

I  36   4 

Nitrogen 

N 

UO4 

13    03 

Bismuth 

Bi 

208  5 

o 

ic  SS 

Boron  

B 

II.  O 

IO.  Q 

Palladium  

Pd 

106.  ? 

ios.  7 

Bromine 

Br 

70   06 

7O    36 

Phosphorus 

p 

•7T       O 

3O    77 

Cadmium  

Cd 

112.  4 

in.  6 

Platinum  

Pt 

104-  8 

IQ3-  3 

Calcium  

Ca 

40    I 

30  8 

Potassium 

K 

•7Q      I  C 

38  86 

Carbon  

c 

12.  OO 

1  1  .  01 

Radium 

Ra 

22  ^    O 

22  3    3 

Chlorine  

CI 

•jr.  4.r 

3=;.  18 

Selenium 

Se 

70    2 

78  6 

Chromium 

Cr 

C2     T 

r  T    7 

Silicon 

Si 

28  4 

28    2 

Cobalt  
Copper.  .  . 

Co 
Cu 

59-o 
63  6 

58.56 
6?    I 

Silver  
Sodium 

Ag 

Na 

107.93 

23    OZ 

107.  12 
22    88 

Fluorine  

F 

IQ    O 

18  o 

Strontium 

Sr 

87  6 

86  04 

Gold  

Au 

107.  2 

IQC    7 

Sulphur 

s 

32    06 

31    83 

Helium  

He 

4.  o 

4  ° 

Tin 

Sn 

1  10    O 

118  i 

Hydrogen 

H 

I    008 

I    OOO 

Titanium 

Ti 

48    I 

47    7 

Iodine 

I 

126   Q7 

126  01 

Tungsten 

W 

184  o 

182  6 

Iron  ...    . 

Fe 

re   O 

r  t    c 

Uranium 

u 

238    £ 

236   7 

Lead  
Lithium  

Pb 
Li 

206.9 

7.  O3 

205-35 
6.98 

Vanadium  
Yttrium  

V 

Yt 

51.2 
89.0 

88'  3 

Magnesium  
Manganese  

Mg 

Mn 

24.36 

55-° 

24.18 

54-6 

Zinc  
Zirconium  

Zn 
Zr 

65-4 

90.  6 

64.9 
89.9 

TABLE    II. —COMPARISON    OF    ENGLISH    AND    METRIC    SYSTEMS. 

i  milligram  =  o.ooi  gram  =    0.01543  grain, 
i  gram  15.432349  grains  =  0.0022  pound, 

i  kilogram   =  1000  grams  =     2.2046  pounds  Avoirdupois, 
i  grain  =     o.  064799  gram.  i  liter  =  61. 028  cubic  inches, 

i  ounce  Avoirdupois    =    28.  3496  grams.  i  liter  =     o.  220215  Imperial 

i  pound  Avoirdupois  =  453.59  grams.  gallon. 

i  millimeter  =    0.03937  inch.  i  cubic  inch       =    0.016386  liter, 

i  meter         =  39.37079  inches.  1000  cubic  feet  =  28,315  liters, 

i  inch  =  25.39954  millimeters, 
i  foot  =    0.3048  meter, 
i  square  inch  =  645. 137  square  millimeters, 
i  square  foot  =       0.0929  square  meter, 
i  square  yard  =       0.8361  square  meter, 
i  cubic  inch  =  16,386  cubic  millimeters, 
i  cubic  foot  =  0.028315  cubic  meter. 


301 


302 


GAS   AND   GAS   METERS 


TABLE  III.  —COMPARISON   OF    FAHRENHEIT  AND  CENTIGRADE  SCALES. 


Fahr. 

Cent. 

Fahr. 

Cent. 

Fahr. 

Cent. 

Fahr. 

Cent. 

212 

100.  0 

162 

72.2 

112 

44-4 

62 

16.6 

211 

99-4 

161 

7l.6 

III 

43-8 

61 

16.  i 

210 

98.8 

1  60 

71.1 

110 

43-3 

60 

15-5 

209 

98.3 

159 

7°-5 

109 

42.7 

59 

15.0 

208 

97-7 

158 

70.  o 

1  08 

42.2 

58 

14.4 

207 

97.2 

J57 

69.4 

107 

41.  6 

57 

13.8 

2O6 

96.6 

156 

68.8 

106 

41.  i 

56 

13-3 

205 

96.  i 

i55 

68.3 

i°5 

40.5 

55 

12.7 

204 

95-5 

J54 

67.7 

104 

40.  o 

54 

12.  2 

203 

95-° 

i53 

67.2 

103 

39-4 

53 

ii.  6 

202 

94.4 

J52 

66.6 

102 

38.8 

52 

II.  I 

201 

93-8 

151 

66.1 

IOI 

38.3 

51 

10.5 

200 

93-3 

J50 

65-5 

100 

37-7 

5° 

10.  0 

199 

92.7 

149 

65.  o 

99 

37-2 

49 

9-4 

198 

92.2 

148 

64-4 

98 

36.6 

.48 

8.8 

197 

91.6 

147 

63.8 

97 

36.1 

47 

8-3 

196 

91.1 

146 

63-3 

96 

35-5 

46 

7-7 

195 

90-5 

145 

62.7 

95 

35-° 

45  . 

7-2 

194 

90.  o 

144 

62.2 

94 

34-4 

44 

6.6 

193 

89.4 

143 

61.6 

93 

33-8 

43 

6.1 

192 

88.8 

142 

61.1 

92 

33-3 

42 

5-5 

191 

88.3 

141 

60.5 

91 

32-7 

4i 

5-o 

190 

87.7 

140 

60.0 

90 

32.2 

40 

4-4 

189 

87.2 

139 

59-4 

89 

31.6 

39 

3-8 

1  88 

86.6 

138 

58.8 

88 

3i-i 

38 

3-3 

187 

86.1 

137 

58.3 

87 

30-5 

37 

2.7 

186 

85.5 

136 

57-7 

86 

30.0 

36 

2.  2 

185 

85.0 

135 

57-2 

85 

29.4 

35 

1.6 

184 

84.4 

*34 

56.6 

84 

28.8 

34 

1.  1 

183 

83.8 

133 

56.1 

83 

28.3 

33 

o-5 

182 

83-3 

132 

55-5 

82 

27.7 

32 

0.  0 

181 

82.7 

I31 

55-° 

81 

27.2 



1  80 

82.2 

130 

54-4 

80 

26.6 

179 

81.6 

129 

53-8 

79 

26.  i 

178 

81.  i 

128 

C7.  ? 

78 

2>.  =; 

/ 

177 

80.5 

127 

*JO  O 

52-7 

/ 

77 

00 

25.0 

176' 

80.0 

126 

<2.  2 

76 

24.  4 

/ 

17^ 

70.  4 

12=; 

0 

si.  6 

7=: 

23.8 

/  0 

/  y  *T 
78.8 

o 
124 

0 

51-  I 

/  O 

74 

O 

23.  3 

173 

/ 

78  7 

12  "? 

CQ  C. 

/  > 

77 

o  o 
22  7 

-1  /  o 
1  72 

/    '  v) 

77  7 

*-•*  o 
122 

jw-  J 
ro  O 

/  o 

72 

/ 

22.2 

-1  /  •* 
I7l 

/  /  •  / 

77  2 

121 

ow< 
4.Q  4 

/ 
7l 

21.6 

1  1  *- 
I7O 

it 

76  6 

I2O 

H-y  •  *r 
48  8 

/  * 
7O 

21.  I 

/ 

j  \j  ,  \j 

76  i 

1  10 

H-   *  ^^ 
48  7 

/ 
69 

20.  "? 

1  68 

|  W.  J. 

7C  e. 

y 

118 

*t  •  o 

47.  7 

vyy 

68 

o 
20.  o 

167 

/  0  •  0 

7^0 

117 

T-  /  •  / 
47.  2 

67 

10-  4 

/ 

1  66 

/  0  •  w 

74.4 

/ 
116 

f  /  • 
46.6 

/ 

66 

*-y  •  t 

18.8 



16"? 

7-1.8 

II  f 

46.1 

65 

18.  3 

0 

1  6d 

/  o 

7-3   -2 

0 

1  14. 

4C.  C 

64 

O 

17  7 

±  V/if 

163 

/  o  •  o 
72  7 

j_  j.^ 
112 

TO  •  D 

4?  .  o 

W-T 

6^? 

it 

17  2 

A  wo 

/  ^  •  / 

-1  Lo 

wo 

x  /  •  •* 

APPENDIX 


303 


TABLE    IV.  —  SHOWING    SPECIFIC    GRAVITY,    WEIGHT    AND    SOLUBILITY 
OF    VARIOUS    GASES.1 


Name. 

Sp.  Gr. 
Air=  i  . 

Weight  of  i 
cu.  ft.  in  Ibs. 
avoir. 

Weight  of 
i  cu.  ft.  in 
grains. 

No.  of 
cu.  ft. 
equal 
to  i  Ib. 

Solubility. 
100   vols.  of 
water  ab- 
sorbed. 

Hydrogen  
Light  carburetted  hydrogen 
Ammonia  
Carbon  monoxide  
Olefiant  gas  

0.0691 

o-559 
0.590 
0.967 
0.968 
°-97I3 

I.  OOO 

1.039 

I.  1056 

1.1747 
1-527 

I.  529 

0.00529997 
0.0428753 
0-045253 
o.  0741689 
o.  0742456 
0.07449871 
o.  0767 

0.0796913 

0.08479952 

o.  09009949 
o.  1171209 
o.  1172743 
o.  1723449 
o.  189449 
o.  202488 

37-09 
300.  12 
316.77 
519.18 

5!9-7i 
52I-49 
536-9o 
557.83 
593-59 
630.  69 
819.84 
820.  92 
1206.  41 
1326.  14 
1417.41 

188.  68 

23-32 

22.  09 

13.48 
13.46 
13-42 

I3-°3 
12-54 
11.79 
ii.  09 

8-53 
8.52 

5-8o 
5-27 
4-93 

1.93  vols. 
3.91   vols. 
72,720  vols. 
2  .  43  vols. 
1  6.  15   vols. 
i  .  48  vols. 
i  .  70  vols. 
Not  soluble. 
2  .  99  vols. 
323.  26  vols. 
77.  78  vols. 

100.  20    VOls. 

4276.  60  vols. 
236.  80  vols. 
Not  soluble. 

Nitrogen  
Air  
Nitric  oxide 

Oxygen  
Sulphuretted  hydrogen.  .  .  . 
Nitrous  oxide  
Carbonic  acid  

Sulphurous  acid 

2.247 

2.470 

2.  640 

Chlorine 

Carbon  bisulphide  

Latta's  Hand  Book  of  American  Gas  Engineering  Practice. 


304 


GAS   AND    GAS   METERS 


M  Tj-r*-M 


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t**°  F°~~  t^-OC  CO  CO     ON  ON  ON  OOOl—  ih-  IM 


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APPENDIX  305 


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ON  ON  ON  ON  ON  ON  ON  ON  ON  ON  ON  ON  ON  ON  ON  ON  ON  ON  ON  ON  OOOOOOOOOOOO 


coO  oo    O   CN   LOGO    O    CN)   LOI^-O    CN   Lor^O    CM   LO^ONM    ^-f 
cococO'tTtrtTtLOLOLo  LOO  O  O  O   r^.  t^-  r^  t^-oo  oOoocOONONO-ONOOOOMMMi-tMoici 


OO      M     COO     ON    M     Mf    t^*   ON   CN     't    t^»   ON    CM     *3~   t^*   ON   CM     LO  t^*  ON   CM     "^t  O      ON    M     T^-  NO      ON    M     ^-  O  CO      M     COO   CO      O 
-  '     LO    LOO    O    O    O      t^.    t^    !>.   1>.CO    OOOOCOCNONCNGNOOOOMMMMCN 


CM    COCOCOCO-^-"^--^--^-LOLOLO  LOO  O  O 
~ 


O    O    O    O 


M     ^   1>»   O     CN     LO 

CN     CN     CN     CO  CO   CO 


t~>»  ON  CM     "T  f^»  ON  CN     TT  t-*»  ON  CM 

LO  LO  LO  LOO  O  O  O   t^*  t^- 

ON  ON  ON  ON  ON  ON 


LO  !>•  O     PO  LOCO     M     COO  OO     M 

'     TJ-   rr   t  LO  LO  LO  LONU  NU  NJ_>  \tj    f^  r^  _       .     ________ 


M      M      CN)      CN)      CN)      CM      COCOCOCOTt 


rJ-O     ONM    rf  O     ON  M    CO  LOCO     O 
.  t^  t^.  t^-OO  OOOOOO     ONONONONO 
ON  ON  ON  ON  ON  ON  ON  ON  ON  ON  ON  ON  ON  ON  ON  ON  ON  ON  ON  ON  ON  ON  ON  ON  ON  ON  ON  ON  ON  ON  ON  ON  ON  ON  ON  ON  O 


306 


GAS   AND    GAS   METERS 


TABLE  VI. 


SHOWING    THE   EFFECT   OF   TEMPERATURE    ON 
CANDLEPOWER. 


TESTS    MADE    ON   WATER    GAS,    USING    AN    OPEN    BURNER. 


Temperature    in 

Observed  candle- 

Corrected  candle- 

Increase    or 

Per  cent  in- 

degrees Fahr. 

power. 

power. 

decrease. 

crease  or 
decrease. 

3° 

8.46 

19.27 

2.92 

13.2 

35 

8.82 

20.  09 

2.  10 

9-5 

41 

9.  02 

20.  56 

1.63 

7-3 

5° 

9.46 

2I-55 

o.  64 

2.9 

56 

9.70 

22.  10 

O.O9 

0.4 

60-66 

9-74 

22.  19 

72 

9.91 

22.57 

"o.'3sf" 

i-7 

81 

10.  10 

23.01 

0.821 

3-7 

89 

10.  26 

23-36 

i.i;1 

5-3 

100 

10.84 

24-69 

2.501 

n-3 

Increase. 


TESTS  MADE  ON  COAL  GAS,   USING  LONDON   ARGAND   BURNER. 


35 

8.84 

16.26 

0.17 

I  .0 

4i 

8.85 

16.28 

o.  15 

0.9 

47 

8.87 

16.  32 

o.  09 

°-5 

56 

8.92 

16.41 

o.  02 

0.  I 

6i-6>; 

8.03 

16.  43 

*SJ           \S  J 

70 

vo 

8.94 

A    •  HO 
16.45 

0.021 

0.  I 

81 

8.  97 

16.  50 

o.  O71 

0.4 

87 

9.12 

16.78 

Q-351 

2.  I 

95 

9-52 

i7-5i 

i.oS1 

6.6 

100 

9.76 

17-95 

I-521 

9-3 

1  Increase. 

Room  was  kept  at  60°  F.  throughout  the  tests,  but  the  air  supply  of  the  burner 
was  heated. 


APPENDIX 


307 


TABLE    VII.  —  SHOWING    THE    EFFECT    ON  THE    CANDLEPOWER   OF    AIR 

IN    THE    GAS.1 


Per  cent  loss  of 

Per  cent  loss  of 

Per  cent  air 

Per  cent  loss  of 

candlepower 

Per  cent  air 

Per  cent  loss  of 

candlepower 

in  mixture. 

candlepower. 

per  i  per  cent 

in  mixture. 

candlepower. 

per  i  per  cent 

of  air. 

of  air. 

2.82 

5-72 

2.03 

I7-65 

44.30 

2.51 

4-94 

10.  08 

2.04 

19.84 

5I-I9 

2-58 

5-40 

ii.  24 

2.08 

21.  56 

56.69 

2.63 

8-51 

18.  04 

2.  12 

22.  22 

58.88 

2.65 

8-95 

19.06 

2.13 

24.  16 

64.51 

2.67 

9.  62 

21.  16 

2.  2O 

27.69 

72.82 

2.63 

10.  40 

23-  24 

2.24 

3i-3o 

80.44 

2-57 

ii.  20 

26.66 

2.38 

32-95 

83-36 

2-53 

i2-35 

29.02 

2-35 

34-53 

87.02 

2-52 

12.  8l 

30.48 

2.38 

37-5° 

90.37 

2.41 

15-25 

37.66 

2.47 

40.79 

93.82 

2.3° 

16.98 

42.28 

2.49 

Experiments  were  carried  out  on  a  25  to  27  candlepower  water  gas  with  a  No.  7 
Slit  Union  Bray  burner  with  a  regulated  consumption  of  5  cubic  feet  per  hour. 

1   Royle,  Chemistry  of  Gas  Manufacture. 


TABLE    VIII. —SHOWING    THE    CORRECTIONS    APPLIED    TO    STANDARDS 
FOR    ATMOSPHERIC  CONDITIONS.1 


For  moisture :  — 

Pentane  lamp,  candlepower 

Hefner  lamp,  candlepower  = 
For  barometric  pressure :  — 
Pentane  lamp,  candlepower  = 

Hefner  lamp,  candlepower  = 
Carcel  lamp.     This  varied  3 


=  10  +  o.  066  (10  —  E)  where  E  =  liters  of  water 
vapor  per  cubic  meter  of  dry  air. 

=  o.  914  +  o.  006  (8.  8  —  E). 


=  10  —  o.  008  (760  —  b)  where  b  =  the  barometric 
reading  in  mm.  of  mercury. 

=  0.914  —  o.oooi  (760  —  b). 

per  cent  from  the  mean  during  one  day,  and  so  no 
corrections  were  worked  out  for  it. 


For  carbonic  acid :  — 

Pentane  lamp,  candlepower  =  C'P'  —  o.  297 


Hefner  lamp,  candlepower 


~.^,  (C-o.23)  where  C'P' =  the 
candlepower  corrected  for  aqueous  vapor  and 
C  =  liters  carbonic  acid  per  cubic  meter. 

0.926  —  0.0066  C  where  C  equals  liters  carbonic 
acid  per  cubic  meter  of  dry  and  pure  air. 


Journal  of  Gas  Lighting,  July  7,   1908. 


308 


GAS   AND   GAS   METERS 


Formula  for  the  correction  of  candlepower  for  aqueous  vapor.1 
The  tentative  formula  suggested  is: 

Candlepower  =  i  +  0.0087  (9-3  —  e)  where  e  =  liters  of  water 
vapor  per  cubic  meter  of  dry  air,  and  9.3  is 
the  normal  number  of  liters  of  vapor  per  cubic 
meter  of  dry  air. 

This  formula  to  be  employed  when  candles  are  used  as  standards. 


TABLE  IX.  —  SHOWING  THE   EFFECT  OF   NITROGEN   ON  CANDLEPOWER.2 


Per  cent 

Per  cent 

Per 

Ob- 

Candle- 

Loss 

loss  candle- 

Candle- 

T  ncc 

loss  candle- 

cent 
nitro- 

Rate of 

burning 

served 
candle- 

power  for 
5  ft.  per  hr. 

of 
candle- 

power  for 
each  i  per 

power  for 
5  ft  .  per  hr. 

L/OSS 

candle- 

power  for 
each  i  per 

gen. 

power. 

of  mixture. 

power. 

cent  nitro- 

of gas. 

power. 

cent  nitro- 

gen. 

gen. 

o 

4.    8 

20.  8 

21.8 

21.8 

1.  2 

T-  '    *"* 

4-8 

20.  0 

20.  6 

I.  2 

2.4 

21.  I 

0.7 

1.4 

4.0 

4-9 

IQ.I 

19.  6 

2.  2 

2-5 

20.  4 

1.4 

1-5 

6.2 

4.9 

17.9 

18.5 

3-3 

2-5 

19.7 

2.  I 

1.6 

7.6 

5-4 

18.8 

17.4 

4-4 

2.6 

18.8 

3-o 

1.8 

i-5 

5-3 

20.  7 

19-5 

2-3 

7-  1 

19.7 

2.  I 

6-5 

0 

5-i 

21.4 

21.  0 

21.  0 

2.  I 

5-° 

20.  9 

20.  9 

0.  2 

0.4 

21.  2 

3-5 

S-2 

21.  2 

20.5 

°-5 

0.7 

21.  2 

5-3 

4-7 

18.6 

19.9 

I.  I 

I.O 

21.  0 

8.6 

c.  4 

20.  4 

18.8 

2.  2 

I.  T. 

2O.  6 

n-3 

O  *   *T 

5-6 

20.  I 

18.0 

3-o 

o 

i-3 

20.3 

i5-9 

6.0 

19.7 

16.5 

4-5 

i-3 

19.  6 

First  set  with  Suggs'  Table  Top  burner. 
Second  set  with  Suggs'  London  Argand  D. 


1  Proceedings  American  Gas  Institute,  October,  1907 

2  Massachusetts  State  Gas  Inspector's  Report,  January,  1893. 


APPENDIX 


309 


TABLE    X.  —  SHOWING    THE    EFFECTS    OF    CARBONIC   ACID    ON 
CANDLEPOWER.1 


Per  cent 

Per  cent 

Per 
cent 

car- 
bonic 
acid. 

Rate  of 

burn- 
ing. 

Ob- 
served 
candle- 
power. 

Candle- 
power  for 
5'  per  hr. 
of   mix- 
ture. 

Loss 
of 
candle- 
power. 

loss  candle- 
power  for 
each  i 
per  cent 
carbonic 

Candle- 
power  for 
5'  per  hr. 
of  gas. 

Loss 
of 
candle- 
power. 

loss  candle- 
power  for 
each  i 
per  cent 
carbonic 

acid. 

acid. 

(i)  o 

2.  tC4 

20    ^ 

40.  4 

40.  4 

\  •*•/ 

1.6 

••  •  jt 
2-59 

w-  j 
2O.  2 

39-o 

1.4 

2.  I 

39-6 

0.8 

.  2 

3-o 

2.68 

20.  2 

37-7 

2-7 

2.  2 

38.8 

i-5 

•3 

5-° 

2.79 

20.  I 

35-9 

4-4 

2.  2 

37-8 

25 

.  2 

5-7 

2-75 

19-3 

35-i 

5-2 

2-3 

37-3 

3-i 

•3 

6.9 

2-85 

19.4 

34-1 

6-3 

2.  2 

36.6 

3-7 

•3 

o 

2.76 

20.  6 

37.  3 

37.  3 

8.1 

*,  •   j  \j 

3.36 

20.8 

Old 

31.0 

6-3 

2.  I 

O  /    O 

33-7 

3-6 

.  2 

8.6 

3-40 

20.7 

3°-4 

6.9 

2.  I 

33-3 

4.0 

•  3 

9-9 

3-3i 

19.7 

29.7 

7-6 

2.  I 

33-o 

4-3 

,2 

12.  I 

3-7i 

20.9 

28.  2 

9.1 

2.0 

32.1 

5-2 

.  2 

15-5 

3-73 

19-5 

26.  2 

ii.  i 

1.9 

31.0 

6-3 

,  I 

18.1 

4.09 

20.  I 

24-7 

12.6 

1.9 

30.1 

7-2 

.  I 

(2)  o 

A    74 

20.  o 

21.2 

21.2 

V    / 

2.  0 

T-  •  /  T- 

5-20 

20.  0 

19-3 

1.9 

4.4 

19.7 

i-5 

3=5 

3-3 

5-59 

2O.  2 

!8.I 

3-i 

4.4 

l8.7 

2-5 

3-6 

4-4 

6.  oo 

20.8 

17-3 

3-9 

4.2 

18.1 

3-i 

3-3 

S-2 

6.  ii 

2O.  2 

l6.5 

4-6 

4.2 

17.4 

3-7 

3-4 

6.2 

6-35 

19.7 

15-5 

5-7 

4-3 

16.5 

4.6 

3-5 

(?)  0 

"2.  4-2 

ID  8 

2Q.  O 

2Q.  O 

\o/ 

2.  0 

O       T  O 

3-72 

A  y  * 

20.  4 

•*•  V 

27.4 

i-5 

2.7 

V 

28.0 

I.  0 

i-7 

2.7 

3-79 

20.5 

27.0 

1.9 

2-5 

27.8 

I.  2 

i=5 

3-2 

3-77 

20.  I 

26.6 

2.4 

2.6 

27-5 

i-5 

1.6 

3-5 

3-9° 

20-5 

26.3 

2.7 

2.7 

27.2 

i-7 

i7 

3-8 

3-99 

20.  6 

25.8 

3-2 

2.9 

26.8 

2.2 

2,0 

5-5 

4-3i 

21.0 

24.4 

4.,6 

29 

25.8 

3-2 

2.O 

6.2 

4.72 

22.4 

23-7 

S-2 

2.9 

25-3 

3-7 

2.0 

7-i 

4.87 

22.7 

23-3 

5-7 

2.8 

25.1 

3-9 

1.9 

8.1 

5-  26 

23.1 

22.  O 

6.6 

2.8 

23-9 

4-7 

2.O 

9-2 

5-28 

22.3 

21.  I 

7-5 

2.8 

23.2 

5-4 

2.O 

ii.  i 

5.10 

20.  4 

20.0 

8.6 

2-7 

22.6 

6.0 

1,9 

(4)o 



!6.7 

l6.7 

...... 

1.  1 

5-° 

15-5 

15-5 

I.  2 

"6.'4" 

15-7 

I.O 

5-5 

2.  2 

5-i 

15-3 

I4.6 

2.  I 

5-7 

14.9 

1.8 

4.8 

3-2 

5-8 

15-5 

13-3 

3-4 

6.4 

13-7 

3-o 

5-6 

4-3 

5-7 

14.7 

12.8 

3-9 

5-4 

13-4 

3-3 

4=7 

5-5 

6.6 

14.9 

"•3 

5-4 

5-8 

12.  O 

4-7 

5-1 

(c)  o 

c.  4 

14.  7 

13  6 

13.6 

0 

0.8 

O         r 

5-7 

•*-'r"  / 

14.7 

AO'  " 

12.7 

0.9 

8.4 

Ao 
12.8 

0.8 

7-4 

J-3 

6.2 

I4.8 

11.9 

1.8 

IO.O 

12.  0 

1.6 

9.1 

1.6 

6.2 

14-5 

ii.  6 

2.0 

8.8 

ii.  8 

1.8 

7-9 

2.  I 

6.8 

14-3 

II.  2 

2.4 

8-5 

".S 

2.  I 

7-7 

2.7 

7-i 

I5-I 

10.7 

2.9 

8.0 

II.  O 

2.6 

7-2 

3-3 

8.0 

15-3 

9-5 

4-  1 

9-3 

9.8 

3-8 

8-5 

3-6 

8.4 

14.  6 

8-7 

4.9 

IO.O 

9.0 

4.6 

9-3 

(6)0 

^.  2 

16.  7 

16.  o 

16.  o 

3-8 

3 

5-9 

x          / 

16.8 

14.2 

1.8 

3  ° 

14.8 

i-3 

2.  I 

Massachusetts  State  Gas  Inspector's  Reports,  January,  1889  and  1890. 


GAS   AND    GAS   METERS 


NOTE.  —  Gas  was  burned  from  Bray  slit  burners  marked  from  2  to  7  feet  per  hour. 
The  mixture  was  burned  so  as  to  give  a  well-proportioned  flame  of  about  20  candle- 
power,  the  aim  being  to  burn  each  mixture  under  the  ordinarily  occurring  condi- 
tions best  suited  to  it.  Carbonic  acid  was  measured  in  a  small  meter  reading  to 
one  ten-thousandth  of  a  foot  and  was  mixed  with  the  rich  gas  before  reaching  the 
ordinary  photometer  meter.  The  Methven  slit  was  used  as  a  standard.  The  gas 
was  a  naphtha  gas  containing  some  nitrogen.  In  the  last  three  columns  the  rate  of 
burning  is  supposed  to  be  that  of  the  illuminating  gas  alone.  Series  (2)  employed 
a  coal  gas  enriched  with  naphtha.  Series  (6)  was  the  same  gas  as  in  series  (5),  but 
an  Argand  burner  was  used. 


TABLE    XI. 


TESTS    OF    THE    5-CANDLE    ELLIOTT   LAMP   AGAINST  THE 
HEFNER    LAMP    AND    AGAINST    CANDLES. 


Date. 

Hefner. 

Candles. 

January  25,  1909  

5-6 

5-°4 

January  26,  1909  

5.58 

5-04 

January  26,  1909  

5.58 

5-05 

January  27,  1909  

5-6 

5.01 

January  27,  1909  

5-6 

5-°7 

January  28,  1909  

5-5 

5-°7 

January  28,  1909  

5-5 

5.08 

January  29,  1909  

5-6 

5-°5 

January  29,  1909  

5-5 

5.01 

January  30,  1909  

5-65 

5-14 

January  30,  1909  

5-65 

5-iQ 

Average  

5-58 

5-°7 

APPENDIX  3  1 1 

TABLE    XII.  —  VALUE    OF    A    5-CANDLEPOWER    ELLIOTT    LAMP. 


Date. 

A 

B 

c 

D 

E 

October. 
6th                           

?.o6 

4-  00 

c.  o? 

c;.  02 

7th  
8th 

5-i5 
51  i 

5-°4 
c  oo 

5-04 

5IO 

5.08 

c    10 

5-°7 
c  06 

Qth 

C      12 

SO"? 

512 

5OQ 

«;  08 

loth 

S     O7 

c;  07 

r    10 

•    y 

c  08 

504 

nth                      

4.08 

c  OQ 

c   04 

c  o<c 

1  2th  
i3th      

5.10 

5-°7 

5.08 

5.08 

5-05 

1  4th 

C     O7 

506 

5    O7 

5O7 

506 

i  5  th  

C.  1C 

*?•  07 

C.  06 

5-  oo 

c.o8 

1  6th 

c    ex 

^  oo 

c    10 

c;  08 

c    10 

i  yth 

r    12 

c,  03 

C    IO 

3-  w" 

«c  08 

c    12 

i  8th     .        .    . 

C.  17 

c.  06 

C.  ir 

c  08 

C.  OC 

igth       

C..  O2 

=5.06 

C.  O2 

1C.  OT, 

^.  O7 

20th  

c.o8 

c.  10 

C.  IO 

C.  OQ 

<?.  IO 

2  I  St  

S.o8 

c..  oo 

?.  O2 

">•  o^ 

c.o8 

22d 

r    O7 

51  1 

500 

(C    06 

2?d 

C    II 

c    10 

r    QZ 

r    OQ 

c    07 

J  

24th    . 

<C.  O4 

3.  ±w 

c.  08 

r  .  o? 

r    oZ 

c..  oo 

25th        

5.08 

c.o8 

26th  

c.  06 

c.o8 

Z.  O2 

^-  oc. 

tC.  O7 

2yth 

506 

c    02 

r    08 

5oc 

500 

28th 

r     12 

c    06 

5    O7 

c  08 

5OC 

2Qth 

C    O7 

r    ii 

c    07 

0-  «" 

c  08 

50? 

^oth                      

C.  O2 

i-  11 
<.  OO 

r    04 

504 

<    O'? 

3ist  
November. 

ist 

4-95 

5O2 

5.01 
*    06 

5-04 

5.00 

5oe 

5.02 

501 

2d 

5O6 

?  02 

t    oi 

SOT, 

5    02 

?d 

c.o8 

«;.o6 

c  ot; 

c    02 

la,.:.::  

5.08 

5-°3 

5.08 

5.  06 

5-  wj 

5.06 

Average  

5-°7 

5.06 

5.06 

5.06 

5-°5 

Explanation.  A  =  Value  of  lamp  found  by  comparing  same  with  the  Holder  gas, 
the  candlepower  of  this  gas  having  been  previously  deter- 
mined against  candles. 

B  =  Value  of  lamp  found  by  comparing  same  direct  with  candles. 

C  =  Value  of  lamp  found  as  in  A  but  against  a  different  gas. 

D  =  Average  A,  B,  and  C.  This  value  is  determined  by  9  A.M., 
and  is  used  as  the  value  of  the  lamp  until  4  P.M. 

E  =  Value  of  lamp  at  4  P.M.  found  by  comparing  same  against 
candles,  and  is  used  as  the  value  of  the  lamp  through  the 
night. 


3I2 


GAS  AND  GAS  METERS 


TABLE    XIII. —SHOWING    THE    COMPARISON    OF   THE   CANDLEPOWERS 
OBTAINED    WITH    THE    OLD    D    AND    NEW    F    ARGAND    BURNERS. 


Coal  gas. 


Candle  power  with  — 

Difference  in  candle- 
power  in  favor  of  — 

Candlepower  with  — 

Difference  in  candle- 
power  in  favor  of—  — 

O.D. 

N.F. 

O.D. 

N.F. 

O.D. 

N.F. 

O.D. 

N.F. 

15-3 

12.0 

n-5 

9.1 

13-9 

17.0 
10.7 

17.8 

16.8 

15.0 

iS-3 

17.7 

i5-5 
14.9 
16.4 

i5-7 
16.5 
16.  i 
16.3 

17-3 
17.0 

14-3 

14.0 

12.8 
II.  0 

10.3 
13-3 
19-5 

10.8 
17.1 
16.4 
12.9 
14.  6 
16.0 
14.8 
13.6 
14.1 
i5-i 
15-9 
iS-3 
15-5 
18.3 
17.9 

15-7 

i-3 

0.8 

17.1 

13-7 
12.9 

12.6 

15-5 

12.  0 
12.7 

16.1 

14.5 

12.8 

14.0 
17.7 
17.9 
17-5 

17.8 
18.5 

17.9 
17-3 
19-3 

18.1 
16.  4 
18.9 

18.8 

14-3 
13.0 

i3-i 
16.3 
12.5 
12.7 

15-4 
15.8 
12.4 
14.1 

17-5 
18.5 

17-5 
17.1 
18.0 
17.9 

18.3 
19.4 
17.7 
17.1 
17.4 

i-7 
0.6 

0.  I 

o-5 
0.8 

°-5 

0-5 

I.  2 

2-5 
0.  I 

0.6 

0.7 
0.4 

2.  I 
0.7 

i-7 

0.7 

i-3 
2-3 
0.6 
0.6 
0.8 
0.8 

0.7 

i-3 

O.  I 

0.4 

O.  2 



0.6 

I.  0 
0.  I 

0.7 

0.7 

°-5 

I.O 

0.9 
1.4 

0.4 

i-5 

APPENDIX 


313 


TABLE  XIV.  —  SHOWING  THE  COMPARISON  OF  CANDLEPOWERS  OBTAINED 
WITH  THE  NEW  F  ARGAND  BURNER  AND  THE  NO.  7  SLIT  UNION  BRAY 
BURNER. 


Water  gas. 


Candlepower  with  — 

Difference  in  candle- 
power  in  favor  of  — 

Candlepower  with  — 

Difference  in  candle- 
power  in  favor  of  — 

N.F. 

20.7 
25-5 

20.  2 

18.8 

19.4 

19.6 

17.8 

19.9 
18.9 

21.8 

20.  6 

20.  I 
20.  O 

20.3 
21.4 

20.8 

21.3 
18.7 

18.9 
20.4 

20.  I 
20.7 
21.  O 
21.7 
19.2 

Bray. 

N.F. 

Bray. 

N.F. 

Bray. 

N.F. 

Bray. 

18.7 
27.2 
17.9 
16.4 
20.9 
14.8 

13-5 
21.9 
14.8 

22.  I 
21.  2 

20.7 

16.8 
16.2 
18.2 
18.0 
16.5 

19-3 
19.7 

13-7 

20.8 

21.3 
21.7 
25-9 

20.  2 

2.0 

2-3 

2.4 

19.8 

20.  0 

19.  6 

20.  0 
21.3 
I9.8 
21.8 

19.7 

21.  I 
22.3 
20.5 
20.  2 
2O.  O 

19-3 
20.  6 
20.  I 
20.  2 
21.4 
20.0 
20.  2 
2O.  2 

18.2 

19-3 

16.  o 

20.  I 

20.8 
22.  2 

14-5 
I7.8 
I7.I 

18-3 
23.1 
21.  0 
22.6 

23-3 
21.7 
21-9 
21.5 
20.  I 
22.5 
l8.7 
I9.O 

18.2 

14.2 

20.4 

12.9 
13-1 

21.  O 
19.4 
21.0. 

5-i 

2.  2 

4.2 

i-5 

I.  0 
2.  2 

1-7 

i-5 

2.0 

4.8 
4-3 

4.1 

•3 
•3 

•5 
.  o 

.  2 

•7 

0.8 
1.9 

0.  2 

°-3 
0.6 
0.6 

3-2 
4.  1 
3-2 

2.8 

4-8 

1.4 

I.  2 

J:| 

7-3 
5-i 

0.6 
0.8 

0.7 
0.6 
0.7 
4.2 

I.O 

"6.y 

i-7 
3-4 
0.9 

314 


GAS   AND   GAS   METERS 


TABLE    XV. —SHOWING    THE   CANDLEPOWER   OF    BURNERS  AT 
VARYING  PRESSURES. 


Burner. 

Candlepower  per  cubic  foot  at  pressures  of  — 

i" 

3" 

5" 

No   7  Slit  Union  Bray 

3-95 
3-75 

3-40 

2.  II 
2.56 

3.76 
3.63 

3.38 
2.  O2 
2.60 

3-97 
3-73 

3.61 
2.32 
2.68 

No    7  Union  Jet  Bray 

Gas  Governor  burners  with  aluminum 
tips.  . 

3-foot  steel  tip  
3-foot  American  E.  H.  lava  tip  

NOTE.  Tests  were  made  on  a  j^ater  gas  of  about  19.8  candlepower. 


TABLE    XVI.  — SHOWING    THE    PERCENTAGE    OF    LOSS    OF    LIGHT    BY 
MIXING    AIR    WITH    COAL    GAS.1 


Air. 

Loss  of 
light. 

Air. 

Loss  of 
light. 

Air. 

Loss  of 
light. 

Air. 

Loss  of 
light. 

Per 

Per  cent. 

Per  cent. 

Per  cent. 

Per 

Per  cent. 

Per  cent. 

Per  cent. 

cent. 

cent. 

I 

6 

8 

53 

5 

33 

20 

93 

2 

ii 

9 

64 

6 

44 

3° 

98 

3 

18 

10 

67 

7 

53 

40 

IOO 

4 

26 

i5 

80 

Newbigging's  Hand  Book  for  Gas  Engineers  and  Manufacturers. 


TABLE   XVII.  —  SHOWING  THE   EFFECT  OF   PRESSURE   ON   LUMINOSITY. 


Pressure  of  air  in  inches 

Observed  illumi- 

Pressure of  air  in  inches 

Observed  illumi- 

of mercury. 

nating  power. 

of  mercury. 

nating  power. 

30.2 

IOO   0 

18.2 

37-4 

28.2 

91.4 

16.2 

29.4 

26.2 

80.6 

14.2 

19.8 

24.2 

73-o 

12.2 

12-5 

22.  2 

61.  4 

10.2 

3-6- 

2O.  2 

47-8 

1  Experiments  by  Dr.  Frankland, 


APPENDIX 


315 


TABLE  XVIII.  —  COMPARING  (APPROXIMATELY)  THE  SPECIFIC  GRAVITY 
OF  GAS  (AIR  BEING  i.ooo)  WITH  THE  ILLUMINATING  POWER  IN 
STANDARD  SPERM  CANDLES.1 


Number  of 
candles  . 

Specific 
gravity. 

Number  of 
candles  . 

Specific 
gravity. 

Number  of 
candles. 

Specific 
gravity. 

10  equal 
II  

12  

to 

do 
do 
do 
do 
do 
do 

about  o.  380 
0.392 
0.405 
o.  416 
0.430 
0.443 
.O   4=X 

20  equal  to 
21  do 

about  o.  508 

.  .O    ^22 

29  equal 

30    . 

to  about  o.  662 
do..  o  6^8 

22  do 

O.  S37 

31  •  • 

do 

.0  604 

13  
14  
15  
16  

2  3  .  .  .  .  do 

.  .O.  Z<O 

1,2  .  . 

do 

w  .  wyit 

.  .0  708 

24  do 
25  do 
26  do 
27  do 
28  do 

0.565 
0.585 

o.  605 
o.  625 
.  .0.  641; 

33  
34  
35  
36  

37  •  • 

do., 
do., 
do., 
do., 
do 

.  .  .  .0.  722 

....0.738 

....0.755 
....0.775 

.  .0.  700 

17  .. 

rlo 

0.468 

18  

do 

o.  482 

19  

do 

0.495 

Newbigging's  Hand  Book  for  Gas  Engineers  and  Manufacturers. 


TABLE    XIX.  —  COMPARISON    OF   THE   JUNKER    AND    SARGENT 
CALORIMETERS. 


Sargent. 

Junker. 

Number  of 
tests. 

Rate  in  feet 
per  hour. 

Average  gross 
B.T.U. 

Rate  in  feet 
per  hour. 

Average  gross 
B.T.U. 

Percentage 
efficiency  of 
Sargent  . 

4 

4 

650.  o 

5 

664.  o 

97-4 

4 

5 

661.5 

5 

676.3 

97-3 

4 

6 

665-5 

5 

681.5 

97.2 

5 

7 

654.0 

5 

665.4 

97.8 

4 

5 

658.0 

5 

676.8 

96.  f 

4 

5 

652.  o 

5 

669  .  o  • 

97-  o2 

1  Test  made  with  a  slight  excess  of  air  admitted  to  the  Sargent  burner. 

2  Test  made  with  a  slight  deficiency  of  air  in  the  Sargent  burner. 

TABLE      XX.  — SHOWING      COMPARISON      OF      PRESSURES      STATED      IN 
OUNCES  AND  INCHES  OF   WATER  AND  IN  INCHES  OF   MERCURY. 


Ounces  of 
water. 

Inches  of 
water. 

Inches  of 
mercury. 

Ounces  of 

water. 

Inches  of 
water. 

Inches  of 
mercury. 

o.  146 

0.25 

o.  018 

7-o 

12.  12 

o.  892 

o.  292 

0.51 

0.037 

8.0 

I3-85 

i.  019 

0.438 

0.76 

0.055 

9.0 

15-59 

1.148 

0.584 

I.  01 

0.074 

10.  0 

17.32 

i-275 

I.O 

i-73 

o.  127 

II.  0 

19.  05 

1.402 

2.O 

3-46 

o-255 

12.  0 

20.  78 

1.529 

3-o 

5.20 

0.382 

13.0 

22.52 

1.658 

4.0 

6-93 

0.510 

14.0 

24.25 

I-785 

5-o 

8.66 

0.637 

15.0 

25.98 

I-9I3 

6.0 

10.39 

0.765 

16.  o 

27.71 

2.036 

GAS   AND   GAS  METERS 


TABLE    XXL  — SHOWING    ANALYSES    OF    VARIOUS    GASES. 
Coal  Gas  —  (in  some  cases  enriched  with  oil  gas). 


No. 

C.P. 

Illu- 
min- 
ants. 

CH4 
Per  cent. 

H 
Per  cent. 

CO 

Per  cent. 

N 
Per  cent. 

O 

Per  cent. 

CO2 
Per  cent. 

I 

2 

19.8 
17.9 

% 
6.  19 

c.  44 

37-79 
?c.  74 

45-93 

47-  7O 

6-74 
6.  75 

2.  06 
3.  13 

0-39 

0.90 
i.  24 

3 

4 
c 

16.8 
17.4 
17  8 

5.58 
5-8l 
4    76 

35-l8 

35-45 
36  84 

47.09 
50.20 
48  88 

5.18 
6.63 

7    7O 

5.78 
o.  76 

O    C.4 

o.  09 
0.07 

1.64 
I.  08 

i    28 

1 

7 

18.6 
18.  i 

5.21 

^.  4^ 

37-67 

?C      2? 

49-76 

CT     CQ 

6.03 

7  80 

I-I5 

0.08 

0.  10 

8 

Q 

17.7 
17.8 

5-05 

=;.  40 

37-05 

17.  18 

49.62 
48.62 

6.25 

6.  30 

1-95 
2.  77 

0.04 

0.04 
0.13 

IO 

4.  20 

7C.   "2-? 

52.  8l 

^.84 

1.82 

II 

17.4 

C.  2C 

77.  CO 

49.  o  i 

C.  QQ 

2.  O2 

o.  04 

12 
13 
14 

'I 

18.0 
18-3 
17-3 
17.7 
17.4 

6.  oo 
7-99 
5-25 
4.96 

4    re 

35-33 
37-54 
36.40 

37-  56 

3C,     22 

51-41 

44.87 
47.26 

43-39 

C.O    OC, 

6.61 
6.49 
6-55 
6.52 

6     7C 

0.52 
2.05 
3.46 
6.60 

327 

0.06 

o.  07 

O.  12 
0-97 

o  ^6 

o.  07 

0.99 

0.96 

17 

17.  2 

S.82 

3<?  68 

48    73 

6  74 

•  •/ 

i  8=; 

i  18 

18 

17.2 

5.62 

37    3O 

48    C7 

6  41 

2    IO 

19 

20 

21 

l8.4 
12.9 
12.6 

5.38 
4.90 
6.69 

36.36 
36.  oo 

34.  32 

48.83 
47.24 
4Q.  4Q 

6.68 

5-65 
6  oo 

1.52 

4.66 

2    6l 

0 

0.13 

1.23 
1.42 
0.80 

22 

I?.  C 

3.69 

34.  <K 

C.2.  2O 

7-8=; 

o  oo 

O.  23 

23 
24 

15-4 

13-9 

5-73 
3.  06 

34-53 

37-  22 

43-53 

4Q.  C7 

6.87 

4.  46 

7.84 
3   60 

o.  56 

0.94 
2.  O9 

25 

13-4 

3-83 

33  -°3 

39.61 

6.61 

13-95 

0.99 

1.98 

Water  Gas. 


I 

2 

21.4 

15.0 

1C.  II 

25-9 

10  32 

27.9 

31  82 

25-3 
2t  88 

3-o 

424. 



2.9 
3  63 

3 
4 

24.4 

23.  7 

13-43 

II.  ^1 

22.  70 
23  8l 

29.86 
28  06 

25-25 
27  82 

4.6i 

3  24 

0.30 

o-  wo 

3.85 

«;  ^6 

5 

27.  i 

14.83 

2O  C.Q 

32  IQ 

27  2  C. 

2  31 

2  83 

6 

I 

9 

IO 

22.4 
23.2 
19.4 
19-5 

21.  2 

13.82 
15.68 
14.70 
13.70 

16.  $4 

18.46 
21-83 

24.  10 

28.31 
21.  43 

31.86 
28.37 

30.  oo 

24.42 
31.  OO 

*/  •  -O 

29.85 

26.  72 

I7-50 

23.80 
26.  O3 

4.65 
7.40 
8.12 
2.  tC<J 

o.  26 

0.27 

2.63 

2.48 
6.30 
1-65 

I.  CC 

ii 

22.  9 

20.  26 

18.01 

2Q-  21 

27.  42 

3-  10 

I.  91 

12 

21  6 

14  OQ 

27  16 

28  32 

24  08 

I  27 

c,  08 

13 

14 

20.  2 
22  .  2 

13.24 
12  6l 

15-47 

17  44 

36.84 
33  26 

31-5° 
32  2O 

2.  22 
2  06 

o.  24 

0.49 

2  34 

1C 

17.  0 

I  3  4s. 

14  7s! 

31  Q7 

27  06 

7  OO 

4  87 

16 
17 

18.6 
18.7 

n-34 

Q.  7O 

20.  00 
22  15 

32.23 

•7  C   77 

27.90 
2  C.  44 

2-57 
502 

O.  21 

5-75 

2.  36 

18 

l8.Q 

12.48 

2O  38 

33  ^7 

26  85 

3  rn 

^.  1^ 

19 

21.  7 

12.  06 

1  7  60 

?e  6=; 

28  40 

2  c;o 

3.61 

20 

21.8 

U.  37 

I  ^  02 

36.  02 

27.22 

3  18 

3-  2Q 

21 

24.  7 

15.  40 

22.84 

29.88 

' 

26.  22 

2.80 

2.  77 

22 

23 
24 
25 

0 

14-3 
15.6 

0.  12 

7-97 
11.  07 
17.  10 

1.30 

29.  66 

17-55 
27.22 

52.14 
42.71 

47-77 
24.40 

36.31 

14.87 

16.  24 
24-33 

3-78 
3-92 
4.82 

2.  63 

0.03 
0-34 
0-34 

0-53 

6-331 

o-53 

I.  21 

3-79 

Blue  Gas. 


APPENDIX 


317 


TABLE  XXI.  — Continued. 
Mixed  Coal  and  Water  Gas. 


No. 

Illumi- 
nants  . 

CH4 

H2 

CO 

N 

O 

CO2 

C.P. 

I 

8-53 

3I-°7 

44-79 

14.50 

0.88 

o 

0.23 

19.8 

2 

8.80 

34.78 

46.35 

9-15 

0.92 

0 

o 

18.8 

3 

6-33 

33-98 

43-85 

9-33 

4-77 

o.  69 

1.05 

17-5 

4 

5.6i 

34-24 

48.43 

7.11 

3-24 

0.13 

1.24 

17.4 

5 

6.58 

30.79 

48.52 

12.  67 

0.92 

0 

0.52 

20.  6 

6 

5.63 

34-15 

50.  26 

8-77 

0.84 

0.09 

o.  26 

18.0 

7 

4-44 

35-41 

51.  20 

6-77 

i.  ii 

0 

1.07 

17.2 

8 

6.08 

28.21 

52.41 

8.26 

3-74 

0 

1.30 

17.5 

9 

7-25 

25.14 

42.44 

21.90 

1-57 

0 

1.70 

17.9 

IO 

n-93 

29.87 

36.78 

18.62 

1.81 

o 

0.99 

20.7 

ii 

5.78 

35-  69 

49.I5 

7-29 

i.  08 

0.03 

0.98 

18.5 

12 

7-87 

30-59 

43-13 

12.37 

4.04 

o-34 

1.66 

17.2 

13 

7.00 

30-99 

46.24 

10.97 

3.15 

0.32 

1.33 

18.0 

14 

9.48 

3i-73 

36.90 

14.76 

3.12 

O.  12 

3-89 

20.8 

15 

7-93 

29.49 

42.  20 

13.  51 

4.29 

0.13 

2.45 

16.7 

16 

9.  60 

34.87 

35-42 

14.  26 

3.65 

0.15 

2.05 

20.7 

17 

7.88 

32-43 

44.90 

11.09 

2.99 

o.  56 

0.15 

17-3 

18 

6-57 

36.55 

48.  i  o 

7-93 

o.  76 

O.03 

0.06 

18.2 

19 

5-55 

40.65 

38.20 

8-73 

6.  10 

0.13 

o.  64 

18.8 

20 

6.92 

41.64 

•2O     A  A 

8    74. 

2  .  85 

O    41 

18.8 

21 

6.98 

3i-97 

50.  22 

<->.   y  £j. 

8.64 

o.  60 



W.   if  J. 

i-59 

16.9 

22 

9.  oi 

29.  26 

41.94 

13-58 

2.67 

0-53 

3.00 

19-3 

23 

5-44 

35-32 

49-59 

7-51 

o.  60 

0.03 

1.51 

17-3 

24 

5-  98 

35-  75 

47.27 

10.90 

0.  10 

18.1 

2  " 

5.  59 

76.84 

49.  90 

6.  91 

0.66 

O.  IO 

17.  31 

26 

o   oy 

O           W*T 

76.  7A 

T-y      y^ 

4.O.  O7 

6.  Q7 

o.  61 

O.  TO 

/  o 

1   Same  sample  analyzed  by  two  different  persons  to  show  the  accuracy  of  Hinman's 
apparatus . 

Natural  Gases. 


No 

02 

C02 

C2H4 

CO 

CH4 

C2H6 

H2 

N 

i 

o.  05 

0.  OO 

o.  40 

0.  00 

70.  oo 

16.75 

0.27 

12.38 

2 

0.00 

o-73 

0.86 

0.  00 

77.40 

14.  18 

o.oo 

6.66 

3 

0.  00 

o.  24 

o.  65 

0.00 

88.  10 

7-37 

0.25 

3.60 

4 

trace 

o  o? 

o  40 

80  85 

1  4  .  oo  1 

O.  IO 

A    60 

T- 
c 

O    1C 

'.  WJ 

o.  20 

w.  4-v-f 

o  50 

-'•  ^J 
07     60 

O    7.O  1 

I     50 

£}.*    ^W 

7     60 

6 

Wl  AD 

O.  OO 

O.  TO 

w.  JV-- 
I  .  OO 

yj  •  w 
Q7    6< 

\*t  .  £\J 
O.  25  l 

±  .    JW 

o.  oo 

^'  "^ 

4    80 

7 

0.34 

w*  O 

o.  26 

0.30 

o.  50 

VO     "J 

92.  61 

*0 

2.18 

H"  *JV^ 

3.61 

8 

0.  20 

0.  10 

0.  10 

0 

81.  10 

n-95 

o 

6-39 

9 

0.  00 

0.00 

o.  61 

0 

83.40 

10.31 

o-33 

5-i9 

10 

O.  IO 

0.  00 

0.81 

o 

94.00 

1.97 

o 

2.98 

ii 

0.40 

o.  70 

o.oo 

0.30 

91.50 

o.  oo 

0 

6-97 

12 

0.  22 

o-33 

0.30 

0 

90-30 

4.  26 

0 

4-45 

17 

O.  2O 

o 

o 

14.  8c 

o.  41 

trace 

82.  70 

O 
14 

O.  IO 

0.00 

0.  00 

0 

AT^            0 

97.18 

0 

0.25 

^  .    ^  w 

2.36 

15 

0.  00 

0.92 

0.61 

o 

95-7° 

0 

0 

2.  69 

16 

0.15 

0.81 

0.  10 

0 

92.40 

0 

o 

6.46 

17 

0.  20 

0.83 

o.  50 

O.  IO 

92.90 

o 

o 

5-43 

18 

0.  10 

o.  60 

I.  20 

o.  20 

87.20 

7.03 

0 

3-65 

19 

o.  40 

0.70 

O.  OO 

0 

98.  oo 

0 

0 

0.88 

20 

0.  10 

0 

0 

0 

14-33 

I.  06 

trace 

82.87 

21 

0.  10 

0.  20 

0 

o 

51.80 

o 

o 

46.40 

22 

0.30 

0.15 

o-55 

0 

78.60 

7.71 

o 

12.13 

27 

o 

O    54. 

o 

74.    IO 

o 

trace 

24    85 

O 

24 

trace 

w-  jt 
0.  20 

o.  16 

0 

/^f-  A 
94-3° 

0.36 

0 

T"*          J 

4.6l 

25 

trace 

0.  20 

0 

98.06 

0 

trace 

T-57 

1   Entered  in  original  as  "  other  hydrocarbons." 

With  regard  to  natural  gas,  it  is  of  course  understood  that  the  gas  from  different 
fields  will  vary  very  greatly  in  chemical  composition. 


GAS   AND    GAS   METERS 


TABLE   XXI.  —  Continued. 
Other  Gases. 


No 

Illu- 
min- 

ants. 

CH4 

H2 

CO 

N 

O 

C02 

C.P. 

Kind  of  gas. 

I 

39.08 

55-57 

4.  61 

0 

o.  41 

o.  07 

o.  26 

52.8 

Oil  gas. 

2 

II.IS 

28.68 

11.68 

9.07 

27.83 

3-66 

7-93 

Wood  gas. 

3 

14.91 

10.67 

4-25 

0.89 

54-  76 

12.52 

2.  OO 

9.0 

Oil,  water  and  air 

gas. 

4 

25.14 

27.02 

o.  70 

37-°7 

9-59 

0.48 

28.4    ' 

Oil  and  air  gas. 

5 

14-39 

3°-54 

36-58 

9-15 

3-96 

0.23 

5-15 

28.3 

Baby  process  water 

gas. 

6 

19.  06 

38.10 

0-33 

11.80 

16.  29 

0 

14.42 

23-5 

Mixed   wood    and 

C2H6 

oil  gas. 

7 

19.17 

37-43 

2.25 

14.  26 

10.  65 

0 

16.  24 

2I-5 

Mixed   wood   and 

oil  gas. 

8 

u-57 

32.81 

20.35 

13.96 

8.89 

o.  42 

12.  00 

15.6 

Mixed  wood,  water 

and  coal  gas. 

9 

9.81 

12.21 

3.01 

66.  42 

2.30 

6.251 

(less 

Stoneham,   Mass., 

than) 

g 

gas. 

10 

5.28 

37.  10 

48.62 

<   46 

2  60 

o  8c; 

1  7    3 

Coal  gas  enriched 

0  • 

o/ 

D  •  <+w 

A  •  v/y 

•  W0 

L  1  •  o 

with  cannel. 

ii 

17.  78 

2S.8i 

21;.  02 

6.  18 

2T..T.O 

i  87 

24.   o 

Kendal       process. 

It 

•*"0  •  WJ- 

*o  •  w~ 

*O«  Ow 

•    / 

«&!••  v/ 

Oil,      air      and 

steam     injected 

in  heated  gener- 

ator. 

12 

37.60 

53-35 

8.21 

0.68 

0.08 

0.08 

52.4 

Naphtha  gas. 

13 

5-8 

40.8 

37.6 

5-6 

6.1 

0.4 

3-7 

17-5 

Coke  oven. 

14 

99-  36 

0.04 

0.06 

0.  01 

0.  II 

0.08 

(a) 

about 

Crude  C2H2. 

C2H2 

200 

1  Includes  H2S. 
(a)   Also  H2S  o.  17;  PH3  0.04;   NH3  o.  10;  SiH4  0.03. 


APPENDIX 


319 


SAMPLE   PAGE   FOR   GAS   INSPECTION   NOTE   BOOK. 

Company 

Munic'p'ty -Place  of  test 

Distance miles  from 

Date . .  Kind  of  Gas 


NH    at                   

Readings 

CP. 

S  M    end                          .  . 

S2 

"      start  

(i)        (2)        (3) 

NH3 

(i) 

H2S 

Press. 

Gas,  end  
"     start  

Time 

Bar. 

Candles                

Temp. 

ft.  for  S2 

(2) 
Gas,  end  
"      start  

CORRECTIONS 

(i) 
Meter  % 

Bar  .  . 

Temp  

Gas  

Candles  

(3) 
Gas  end                        

Corr.  C.P  

"      start  

(2) 
Meter  % 

Candles  

Bar  
Temp  
Gas  
Candles  

S2  Mr.  Corr  

Average 

Corr.  C.P  

(3) 
Meter  % 

Burner 

Remarks: 

Bar               

Temp           o 

Lras  
Candles                  .... 

Corr  C  P                           

320 


GAS   AND   GAS   METERS 


SAMPLE   PAGE   FOR   CALORIMETRIC   RECORDS. 

CALORIMETER    TESTS. 


Place .  .  . 
Locality . 
Date .... 
Time .  . 


Water  passed 


Temp, 
inlet    water. 


Average . 


Temp, 
outlet  water. 


Kind  of  gas 


...C.P. 


Meter  at  end .  .  . 
"        "  start.  .  . 
Gas  burned. . 


Length  of  test... 
Temp,  of  room . . 

"       inlet  gas.  . 

"       outlet  gas. 

Barometer 

Meter  error . . 


C.  P.  TEST. 


No.  i. 


Readings. 


Gas  at  end 

"     "  start 

"     burned  


Candles 
Temp. . 
Barom. . 


No.  2. 


Gas  at  end 

"     "  start 

"     burned  


Candles 

Meter  error 


No.  i. 


No.  2. 


Condensation CC  for ft.  gas 

X = B.T.U.  Gross 

. .  X = B.T.U.  Condensation 

..Net 


APPENDIX 


321 


TABLE  XXII.  —  SHOWING  THE  AVERAGE  CAPACITIES  OF  DRY  GAS 
METERS  OF  ALL  MAKES  IN  CUBIC  FEET  PER  HOUR  WITH  0.5  INCH 
ABSORPTION.1 


Size. 

Capacity. 

3-light 

66  cu.  ft. 

5-light 

95  cu.  ft. 

jo-light 

141  cu.  ft. 

2O-light 

218  cu.  ft. 

3o-light 

287  cu.  ft. 

45-light 

315  cu.  ft. 

6o-light 

475  cu-  ft- 

loo-light 

750  cu.  ft. 

i5o-light 

1175  cu.  ft. 

200-light 

1600  cu.  ft. 

3oo-light 

2050  cu.  ft. 

5oo-light 

3300  cu.  ft. 

1  Catalogue  of  the  Pittsburg  Meter  Company. 

TABLE  XXIII.  — PRESSURES  IN  INCHES  OF  WATER  AND  IN  POUNDS 

AND  OUNCES. 


Inches. 

Lbs.       Oz. 

Inches. 

Lbs.       Oz. 

Inches. 

Lbs.     Oz. 

I 

o     0.59 

15 

o       8.82 

29 

I.  06 

2 

o     1.18 

16 

o       9.41 

3° 

i-65 

3 

o     i.  76 

17 

O       IO.OO 

3i 

2.24 

4 

o     2.35 

1  8 

o     10.59 

32 

2.82 

5 

o     2.94 

19 

o     ii.  18 

33 

3-4i 

6 

o     3-53 

20 

o     11.76 

34 

4.00 

7 

O       4.  12 

21 

o     12.35 

35 

4-59 

8 

o     4.71 

22 

o     12.94 

36 

5.18 

9 

o     5.29 

23 

o     13-53 

37 

5-76 

10 

o     5.88 

24 

O       14.  12 

38 

6-35 

ii 

o     6.47 

25 

o     14.71 

39 

6.94 

12 

o     7.06 

26 

o     15.29 

40 

7-53 

T  *? 

_        *.    /;  - 

*?  *7 

o     15.88 

T  A 

o     8.  24 

*  1 
28 

I         O   d.7 

*•'+ 

X              \J  .  if  1 

322 


GAS  AND   GAS   METERS 


co    H 

el 
gg 


§  o 
o  S 


PH   *o 


.5  £ 

*  I 


II 


8  2 
°  fc 


-I 

-M  8  a 

2 


S  o 
"  fc 
t,  a> 

^•s 


M  u 

.s  ^ 

l"S  I 

,   o  a 


fe 


II 


M    O    ON  O  O    M    ro  toOC    N  O    M    t~-  f}  OO    Tf  C*    M    O    O    O 
HH    tOOO    IN    t^  HI    to  O  COOO    M    t~*  M  O    QtoO^OOtoOto 

MOO  OOO  OO    C^»O  OvoiOTJ-rj-rorON    M    M    M    6    O    O 

++++++++++++++++++++    I 

8to  O    to  O    to  O    to  O    to  O    to  Q   to  O   voO   voO    iOO    >^ 
OMMCNdCOfO^t^iO  uo\O  O    f^-  t-»OO  OO    O  O  O    O 

6^'c^O\O\O^OvO^O>O»O>O 

to  P*    O^^O    cs    OvO    ro  OO    N    o^O'-i   t^-rOO^Oi-i   r-^fOO 
t-^C\O   <N   ^fiot^ONO   w   "3-i-or^ONO   w   f)io  t^.oo   O    M 

t^.  t^»oO  OOOOOOOOCX5    OQ^O^O^OC^O    O    O    O    O    O    M    M 

MiiiiiiiiiMirrrrrrrr 

CS    to  Tf  ioO    t^-OO    O  O    M    <N    ro  Tf  u-j-O    t^GO    O  O    M    <N    ^O 

to   '  *o  >o 

MOOOOOOOOO  OCO    t^-  t^\C    to  T)-  fO  <N    M    O    O 

ooo   ^M   o   c^   ^0  r^o>-i   fOtot^OM  fOtoi^-OM   cs 

OOOOo66oOO'-i'-i|-l'-iMWCSM(N(NrofO 

+  +  +  +     I   I   I   I   I   I   I   I   I   I   I   I   I   I   I   I   I 

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MOOO    rOMOOO    ^-  M    O1>-^1-M    Ot^-tofOOOOO    rOM 

^6006000  ooo  oo  oo  oo  * 

O    M    w    fO  rt-  tOMD    I>-00    O  O    M    n    fO  rf  toO    t~-00    O  O    M 
tototototototototo  toO  OOOOOOOOO   r^t^- 

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J>-  t^-OO'  00    OOOO    6    M    M    M    (S    (N    rorOfo444toto 
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CS    rO  f*O 

(N 

to  toOO    O    ^  O  f5  OO    fOMOOOQi-irO  toOO    (N  O    M 
O    OcsO    OMO    orOt^M    tOOO    c<    t~~  M   to  O  fOOO    M    t-» 

M    M    M    6    O  OOO  OO    t^-O  O    to  to  4 
+++++++++++ 

O    M    w    fO  ^t"  ioO   r^oo    O  O    w    c*   co  ^  voO   f^oO    ON  O 
t^»  t^*  r^-  x>*  t>*  t^*  r^»  r**  t^»  IN»OO  oc  00  oo  oo  oo  oo  oo  oo  oo   ^ 


APPENDIX 


323 


t"*-  fO  ONO    ^"   C^    M    O    O    O    ONOO  O    TJ-   M  OO    t/ 

MO      O     >OO     IOO     IOO     tO   ON    -3-    ON   Tf    ON   fOOO 


(N    rr>  Tf  toO    t^OO    ON  O    M    N    ro  •<*•  toO    t^oO    CN  O    M    n 


INDEX. 


Absorption  of  —  PAGE 

carbon  dioxide 165,  166 

illuminants 172 

oxygen 166-169 

Acetylene  — 

amount  of  impurities  in 141 

analysis  of 174,  175 

burners  for „ 42 

carbon  dioxide  in 95 

causes  of  low  candlepower 76 

determination  of  arsenic  in 138,  139 

sulphur  and  phosphorus  in 140 

occurrence  of  arsenic  in 142 

pressure  for 252 

procedure  for  candlepower  of 68,  69 

qualitative  test  for  arsenic  in 141 

sulphuretted  hydrogen  in,  cause  of 15 

Aerorthometer 121-123 

Air,  effect  of,  on  candlepower  of  coal  gas 307,  314 

Alcohol,  absolute,  as  absorbent  for  illuminants 172 

American  standard  cubic  foot 272 

Ammonia  — 

determination  of,  by  Lacey's  method 151-153 

Mass,  method 145-149 

Mass,  method,  solutions  for 146-7 

Mass,  method,  precautions 148-9 

Referees'  method 149-151 

Referees'  method,  calculations 150-1 

Referees'  method,  criticisms 151 

need  of  a  limit  for 154 

origin  in  gas 143,  144 

why  removed  from  gas 143 

Amylacetate  — 

manufactures  and  properties 30 

testing  of 66,  67 

Analyses  — 

gas,  interpretation  of 192,  193 

table  of 316-318 

samples  for 164-165 

325 


326  INDEX 

Apparatus  —  PAGE 

for  gas  analysis 175-188 

Elliott's 178-179 

Hempel's .  . 175-178 

Hinman's 182-188 

Orsat-Lunge 179-182 

other  forms 191 

Taplay's 178 

Arch  pressure  gauge 256 

Argand  burners  — 

candlepower  with 312 

chimneys  for 42 

sizes 41-42 

Arsenic  — 

determination,  in  acetylene 138,  139 

manner  of  occurrence,  in  acetylene 142 

qualitative  test  for,  in  acetylene 141 

why  objectionable,  in  acetylene 142 

Atomic  weights,  table  of 301 

Automatic  calorimeter,  Junker 241 

Balance  — 

for  candles 22 

Lux 259 

Beasley  calorimeter 239 

Benzene  — 

absorption,  in  gas  analysis 172-173 

effect  of  cyanogen  on  determination  of 173 

Blow-off,  desirability  of 6 

Bougie  de  PEtoile 25 

Boys  calorimeter  — 

criticisms  of 217,  218 

description 210-215 

method  of  using 215-217 

Bray  burner,  candlepower  with 313 

Bristol  pressure  gauge 253--256 

British  Thermal  Unit,  definition 198 

Bromine  as  absorbent  for  illuminants 172 

Burners  — 

air  supply  for 39 

Argand,  sizes  to  be  used 41,42 

considerations  governing  choice  of 39-41 

for  acetylene 42 

for  gasolene  gas 42 

for  oil  gas 42 

for  photometric  work 38-42 

Metropolitan  No.  2 39 


INDEX  327 

Calculations  —  PAGE 

candlepower 56-60 

with  pentane 65 

Calorie,  definition 198 

Calorific  value  — 

determination,  by  analysis 242-243 

Casaubon's  method 237 

Jones'  method 238 

of  gas,  in  various  places 243-246 

relation  to  candlepower  and  flame  temperature 246-9 

standards  for 246 

Calorimeters  — 

automatic  Junker 241 

Beasley .     239 

Boys,  criticisms  of 217,  218 

description ...     210-215 

method  of  using 215-217 

classes  of 198,  199 

'    comparison  of  Junker  and  Sargent 315 

Fery 239 

Graefe 241 

Junker,  calculation  of  results  with 206,  207 

description 199-202 

discussion  of 209,  210 

method  of  using 202-206 

precautions  regarding  use  of 205,  206 

Raupp's 239 

Sargent,  calculation  of  results  with 230-231 

criticism  of 231-235 

description  of 226-229 

method  of  using 229-230 

Schonberger's 240 

Simmance-Abady,    calculation  of  results  with 223-224 

criticisms  of 224-226 

description  of 219-221 

method  of  using 222,  223 

portable 235,  236 

testing  of. 221 

Stoecker  &  Rothenbach's 240 

types  approved 236 

water  supply  for 203,  204 

Calorimetric  results,  how  reported 207-208 

Calorimetry  — 

definition  of 198 

importance  of , 197 

terms  used  in,  defined 198 


328  INDEX 

PAGE 

Candle  Balance 22 

precautions  regarding 46 

Candlepower  — 

and  specific  gravity,  relation 315 

calculations 56-60 

with  pentane 65 

effect  of  air  on 74,  307,  314 

carbon  dioxide  on 309 

nitrogen  on 308 

pressure  on 314 

temperature  on 306 

factors  affecting  —  of  coal  gas 7°~74 

of  acetylene,  procedure  for 68,  69 

of  constituents  of  gas 72 

of  gasolene  gas,  procedure  for 69 

of  natural  gas,  procedure  for 69 

of  oil  gas,  procedure  for 68 

relation  to  calorific  value 246-249 

requirements,  in  various  places 79~8i 

suggestions  for  reading  disc 55 

test,  details  of 54~56 

preparations  for 45~S4 

with  N.  F.  and  O.  D.  Argand  burners,  table 312 

with  N.  F.  and  No.  7  slit  union  Bray  burners,  table 313 

Candlepowers,  table  of,  at  varying  pressures 314 

Candles  — 

Bougie  de  1'Etoile 25 

causes  of  abnormal  burning  of 53~54 

correction  for  rate  of  burning 58 

cutting 51,  52 

definition  of  light  of 28 

extinguishing 56 

history  of,  in  photometry 24-26 

how  to  light 52,  53 

kind  to  be  used 50 

Munich , 25 

Paraffin 25 

position  of  wicks  of 52 

sperm,  disadvantages  of 26-27 

effect  of  altitude  on  burning  of 27 

specifications  for 25-26 

stearine 25 

tallow 24 

wax 24,  25 

when  burning  properly 53 

which  end  to  light 51 

wick  the  weak  point  of 26 


INDEX  329 

PAGE 

Capacities  of  meters 321 

Carbon  bisulphide  — 

determination I37>  J38 

dioxide,  absorption  of 165,  166 

calculation  of  percentage,  from  gravimetric  analysis 88 

determination  in  general 86-92 

effect  on  candlepower 309 

gravimetric  determination  of 88 

in  acetylene 95 

in  crude  coal  gas 95 

in  crude  water  gas 96 

in  natural  gas 95 

in  purified  coal  gas 96 

qualitative  test  for 94 

reaction  with  caustic  potash 86 

recording  apparatus  for 94 

volumetric  determination  of 89-94 

calculation  of  results 91 

Hempel's  method 92 

Rlidorff's  method 92-93 

solutions  for 89-91 

Carbonizing  period,  effect  of,  on  gas 73 

Carbon  monoxide  — 

absorption  of 169-171 

determination  by  explosion 171 

lack  of  restrictions  for 163 

Carcel  lamp,  construction  and  fuel 28,  29 

Casaubon's  method  for  calorific  value 237 

Caustic  potash  for  absorption  of  carbon  monoxide 165,  166 

Chilling,  effect  on  candlepower 74 

Chimneys  for  use  with  Argand  burners 42 

Chromous  chloride  as  absorbent  for  oxygen 167,  168 

Coal,  analysis  of 70 

Colman  &  Smith  method  for  naphthalene 158-162 

Colza  oil 29 

Copper  as  absorbent  for  oxygen 169 

Corrections  — 

for  temperature  and  pressure  in  photometry 57>  5& 

table  of,  for  temperature  and  pressure 304,  305 

Cubic  foot  — 

American 272 

comparative  value  of  forms  of 285,  286 

English 271 

standardization  of 273 

water  bottle 274 

Cuprous  chloride  as  absorbent  for  carbon  monoxide 169-171 


330  INDEX 

Cyanogen —  PAG« 

amount  in  gas , 162,  163 

determination  of 163 

effect  on  determination  of  benzene 173 

in  gas,  how  removed 163 

Discs,  used  with  photometer 22 

Edgerton  standard  — 

accuracy  of 35 

construction  of 35 

disadvantages  of 35 

use  of 66 

Effusion  tests  for  specific  gravity 260-263 

Eitner  &  Keppeler  method  for  sulphur  and  phosphorus  in  acetylene 140 

Electric  standards 38 

Elliott's  — 

apparatus  for  gas  analysis 178,  179 

lamp,  advantages  of 33 

candlepower  determination  with 65 

construction  and  fuel  of 3I-32 

defect  in 34 

tests  of 33,  311 

English  cubic  foot 271 

Enrichers 71 

Explosion  — 

determination  of  carbon  monoxide  by 171 

hydrogen  by 174 

Explosions,  use  of  Wimshurst  machine  for 188 

Extinguishing  candles 56 

Eery  calorimeter 239 

Flame  temperature,  relation  to  calorific  value *. 246-249 

Gas  — 

acetylene,  causes  of  low  candlepower  of 76 

coal,  candlepowers  of  constituents  of 72 

effect  of  air  on  candlepower  of 74 

carbonizing  period  on  candlepower 73 

chilling  on  candlepower 74 

constituents  on  candlepower 73 

temperature  on  composition 72 

treatment  in  retorts,  etc.,  on 71,  72 

washing  on 74 

corrections  for  temperature  and  pressure 57~58 

oil,  causes  of  low  candlepower  of 76,  77 

regulating  to  5  feet  per  hour 49 


INDEX  331 

Gas  —  PAGE 

results  obtained  as  to  candlepower  of 77~79 

stale,  clearing  from  pipes , 47 

use  of,  in  testing  meters 292,  293 

water,  factors  decreasing  candlepower  of 74~76 

reactions  in  making 74 

Gases  — 

calorific  value  of  various 243 

specific  gravity,  weight  and  solubility  of  various 303 

Gasolene  gas  — 

burners  for 42 

procedure  for  candlepower  of 69 

Generator,  hydrogen 187 

Governor  — 

for  use  with  photometer 21 

regulating,  on  photometer 50 

Graefe  calorimeter 241 

Harcourt  — 

method  for  sulphur no-i  14 

sulphuretted  hydrogen 104 

Harding  &  Doran  method  for  carbon  bisulphide 137,  138 

Hefner  lamp  — 

candlepower  determination  with 67,  68 

construction  and  fuel  of 29,  30 

criticisms  of 30,  3 1 

Hempel's  gas  analysis  apparatus 175-178 

method  for  carbon  dioxide 92 

Hinman's  gas  analysis  apparatus 182-188 

advantages  of 189 

calculations  with 190,  191 

precautions  regarding 189 

Hinman- Jenkins  method  for  total  sulphur 126-137 

Hydrogen  — 

absorption  of,  in  gas  analysis 173,  174 

determination  by  explosion  recommended 174 

generator,  for  gas  analysis - 187 

Illuminants,  absorption  of,  in  gas  analysis 172 

Impurities  present  in  gas 85 

Interpretation  of  results  of  analysis 192,  193 

Jet  photometers 265 

Jones'  method  for  calorific  value 238 

Junker  — 

automatic  calorimeter 241 

calorimeter,  calculating  results  from 206-7 


332  INDEX 

Junker  —  PAGE 

calorimeter,  compared  with  Sargent 315 

description 199-202 

discussion  of 209-210 

method  of  using 202-206 

Lacey's  method  for  ammonia 151-153 

Lamp  — 

Carcel 28,  29 

Elliott 31,  34,  65 

test  of  a  5-candle 311 

Hefner 29-31,  67-68 

Latent  heat  of  steam,  term  explained 198 

Lead  acetate  — 

reaction  with  sulphuretted  hydrogen 98 

strength  for  sulphuretted  hydrogen  test 99 

Leak- 

correction  for,  in  photometric  test 59 

testing  for,  in  photometric  test 48 

Lime,  removal  of  sulphur  by 109 

Lux  balance 259 

calibration  of 260 

Mass,  method  for  ammonia 145-149 

specific  gravity 261-263 

Meter  — 

saturating  water  of  wet 46,  49 

setting  water  level  of  wet 47,  48 

wet,  used  with  photometer 21 

Meter  provers  — 

care  of 281 

description  of 274-278 

purpose  of  weights  on 281-282 

setting  up 279-281 

standardization  of 282-285 

standards  for  testing  of 270-274 

Meters  — 

capacities  of,  table 321 

calculation  of  error  of 293-297 

dry,  why  tested 269-270 

general  per  cent  error  found  in  testing 299 

laws  regarding  accuracy  of 299 

open-top,  how  tested 298 

point  on  dial  to  commence  test 290 

rates  used  in  testing 290-291 

table  of  errors  of 322-323 

wet,  how  tested 297,  298 

marking  water  line  of 298 


INDEX  333 

Meter  testing  —  PAGE 

difficulties  met  in 292 

importance  of  temperature  in 287 

procedure  in 288-292 

use  of  gas  in 292,  293 

Methven  screen 36 

Metric  system  compared  with  English 301 

Metropolitan  No.  2  burner 39 

Mohr's  method  for  sulphuretted  hydrogen 100-104 

Munich  candles 25 

Naphthalene  — 

deposition  of,  from  gas 156,  158 

determination,  calculations  for 162 

Colman  and  Smith's  method 158-162 

formation  of,  in  gas iSS 

qualitative  test  for 158 

vapor  pressure  of 156 

White  and  Barnes'  experiments  on 157 

Natural  gas  — 

carbon  dioxide  in 95 

pressure  of 253 

procedure  for  candlepower  of 69 

Net  heating  value,  reasons  for  not  reporting 207,  208 

Nickel  hydrate,  as  absorbent  for  benzene 172 

Nitrogen  — 

effect  on  candlepower 308 

method  for,  in  gas  analysis 174 

Nordhausen  acid,  as  absorbent  for  illuminants 172 

Oil,  colza 29 

Oil  gas  — 

burners  for 42 

candlepower  of,  procedure  for  . 68 

causes  of  low  candlepower 76,  77 

Orsat-Lunge  apparatus  for  gas  analysis 179-182 

Oxide,  effect  on  total  sulphur no 

Oxygen  — 

absorption  of 166-169 

absorption  by  sodium  hydrosulphite 169 

Palladium  — 

as  absorbent  for  hydrogen 173 

black,  preparation  of *74 

sponge,  preparation  of 173 

Paraffin  candles 25 


334  INDEX 

Pentane  —  PAGE 

preparation  of 61 

testing  of 61,  62 

Pentane  lamp  — 

construction 36,  37 

disadvantages  of 38 

fuel  for 37 

standardizing 62 

test  of  candlepower  with 63,  64 

Phosphorus  — 

as  absorbent  for  oxygen 166 

determination  in  acetylene 138,  139,  141 

manner  of  occurrence  in  acetylene 142 

why  objectionable  in  acetylene 142 

Photometer  — 

Rumford's 20 

Selenium 19 

size  recommended 9,  10 

stationary 7-1 1 

Suggs-Letheby,  advantages  of 8-10 

table ii 

Wild  Flicker 19 

Photometer  room  — 

color  of 6 

construction  of 5,6 

location  of 3,4 

temperature  of 5,6 

ventilation  of 5,6 

Photometers  — 

closed  bar,  construction  of 7,8 

cost  of 10 

formula  for  calculating  the  position  of  any  mark  on 44 

grating 20 

jet 21,  265 

measurement  of 43~45 

piping  for 6-7 

portable,  description 11-14 

method  of  using 14-16 

objections  to ,     16,  17 

recent  form  of 18 

recent,  references  to 21 

Portable  calorimeter,  Simmance-Abady 235-236 

Potassium,  as  absorbent  for  hydrogen 173 

Pressure  — 

effect  on  candlepower 314 

efficiency  of  Welsbachs 250,  251 

requirements  for 250,  251 


INDEX  335 

Pressure  —  PAGE 

table  of,  in  air  and  ounces  of  water  and  inches  of  mercury 315 

in  ounces  and  pounds  of  water 321 

with  acetylene 252 

Pressure  gauge  — 

Arch 256 

Bristol : .  . .  .      253-256 

minimum  limit  needed 252 

precautions  in  taking 257 

siphon 256 

U ' 256 

with  natural  gas 253 

Provers,  see  meter  provers. 

Pyrogallic  acid,  for  absorption  of  oxygen 167 

Rates  for  testing  meters 290,  291 

Raupp's  calorimeter 239 

Records  — 

sample  page  for  calorimetric 320 

gas-book 319 

Recording  apparatus  for  carbon  dioxide 94 

Referees'  method  for  ammonia 149-151 

sulphur 118-126 

Results,  calorimetric,  how  reported 207-208 

Retorts,  effect  on  gas  of  treatment  in . 71,  72 

Riidorff 's  method  for  carbon  dioxide 92,  93 

Sample  —  for  gas  analysis 164,  165 

Sample  tube  for  gas  analysis , 165 

Sargent  calorimeter  — 

calculating  results  with 230,  231 

criticism  of 231-235 

description  of 226-229 

method  of  using 229-230 

Schilling's  apparatus 261 

Schonberger's  calorimeter 240 

Screen,  Methven 36 

Sight  box 23 

Silica  — 

determination  in  acetylene 138,  140,  141 

manner  of  occurrence  in  acetylene 142 

why  objectionable  in  acetylene 142 

Simmance-Abady  calorimeter  — 

calculating  results  with 223-224 

criticism  of 224-226 

description  of 219-221 

method  of  using 222-223 

testing  of •  •  •  •      221 

Simmance-Abady  portable  calorimeter 235-236 


336  INDEX 

PAr, 

Siphon  pressure  gauge 256 

Sodium,  as  absorbent  for  hydrogen 173 

Sodium  hydrosulphite,  as  absorbent  for  oxygen 169 

Solubilities  of  gases,  table  of 303 

Specific  gravity  — 

calculation  of,  from  analysis 263 

definition  of 258 

determination,  by  Lux  balance 259 

effusion  tests 260-263 

Mass,  method 261-263 

of  various  gases 303 

relation  to  candlepower 315 

Schilling's  apparatus  for 261 

table  of,  of  gases 303 

value  of  determination 258 

Sperm  candles 25-27 

Stale  gas,  clearing  from  pipes 47 

Standard,  Edgerton 66 

Standards  — 

corrections  applied  to,  for  atmospheric  conditions 307-308 

for  calorific  value 246 

for  photometrical  work 24-38 

in  practical  use  in  photometry 24 

Standardization  — 

of  cubic  foot 273 

of  meter  provers 282-285 

Steam,  latent  heat  of,  explanation  of  term 198 

Stearine  candles 25 

Stoecker  and  Rothenbach's  calorimeter 240 

Sulphur  — 

manner  present  in  coal 96 

total  amount  in  water  gas 97 

determination,  Harcourt's  method 110-113 

criticisms 113-114 

Hinman- Jenkins'  method 126-137 

accuracy,  etc 136 

apparatus 126-128 

method,  theory 134-136 

reagents 129-133 

in  acetylene 138-141 

Referees'  method 118-126 

calculations 125 

criticisms  of 125,  126 

theory  of 123,  124 

Wildenstein's  method 114-116 

Young's  method 1 16-1 18 

legislation  regarding 106-109 


INDEX  337 

Sulphur  —  PAGE 

total  need  of  limit  for 155 

removal  by  lime  purification 109 

Sulphuretted  hydrogen  — 

amount  in  crude  coal  and  water  gas 96,  97 

cause  of  excess  in  gas 105 

Harcourt's  method  for 104 

in  acetylene,  cause  of 97 

Mohr's  method  for 100-104 

need  of  a  limit  for 1 54 

origin  in  gas 96 

qualitative  test  for 98,  99 

quantitative  estimation  of 100-104 

in  acetylene 104,  105 

solutions  for 101 

removal  by  oxide 109,  1 10 

strength  of  lead  acetate  for  test 99 

why  objectionable 97,  98 

Sulphuric  acid  — 

as  absorbent  for  benzene 173 

fuming,  as  absorbent  for  illuminants 172 

Tallow  candles 24 

Taplay's  apparatus  for  gas  analysis 178 

Temperature  — 

and  pressure,  corrections  for 304,  305 

effect  on  candlepower 306 

composition  of  coal  gas 72 

Thermometers,  comparison  of  Fahrenheit  and  Centigrade  scales  of 302 

U  gauge 256 

Washing,  effect  on  candlepower  of  gas 74 

Water  bottle 274 

Water  level,  setting  of,  in  wet  meter 47,  48 

Water  supply,  for  calorimeter 203,  204 

Wax  candles 24,  25 

Weight  of  gases,  table  of 303 

Welsbachs,  effect  of  pressure  on  efficiency  of 250,  251 

White  and  Barnes'  experiments  on  naphthalene 157 

Wick,  weak  point  of  candles 26 

Wildenstein's  method  for  total  sulphur 114-116 

Wimshurst  machine,  for  explosions 188 

Yield,  proper,  of  coal  gas   70 

Young's  method  for  total  sulphur 116-118 


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*  Holleman's    Laboratory   Manual    of   Organic    Chemistry  for   Beginners. 

(Walked "mo,  i  oo 

Text-book  of  Inorganic  Chemistry.     (Cooper). 8vo,  2  50 

Text-book  of  Organic  Chemistry.     (Walker  and  Mott) 8vo,  2  50 

4 


olley  and  Ladd's  Analysis  of  Mixed  Paints,  Color  Pigments,  and  Varnishes. 

Large  12 mo,  2  50 

Hopkins's  Oil-chemists'  Handbook 8vo,  3  oo 

Iddings's  Rock  Minerals 8vo,  5  oo 

Jackson's  Directions  for  Laboratory  Work  in  Physiological  Chemistry.  .8vo,  I  25 

Johannsen's  Determination  of  Rock-forming  Minerals  in  Thin  Sections. .  .8vo,  4  oo 
Johnson's  Chemical  Analysis  of  Special  Steel.     Steel-making.     (Alloys  and 
Graphite.)     (In  Press.) 

Keep's  Cast  Iron 8vo,  2  50 

Ladd's  Manual  of  Quantitative  Chemical  Analysis i2mo,  i  oo 

JLandauer's  Spectrum  Analysis.     (Tingle) 8vo,  3  oo 

*  Langworthy  and  Austen's  Occurrence   of  Aluminium  in  Vegetable  Prod- 

ucts, Animal  Products,  and  Natural  Waters 8vo,  2  oo 

Lassar-Cohn's  Application  of  Some  General  Reactions  to  Investigations  in 

Organic  Chemistry.  (Tingle) i2mo,  i  oo 

Leach's  Inspection  and  Analysis  of  Food  with  Special  Reference  to  State 

Control 8vo,  7  50 

Lob's  Electrochemistry  of  Organic  Compounds.  (Lorenz) 8vo,  3  oo 

Lodge's  Notes  on  Assaying  and  Metallurgical  Laboratory  Experiments 8vo,  3  oo 

Low's  Technical  Method  of  Ore  Analysis 8vo,  3  oo 

Lunge's  Techno-chemical  Analysis.  (Cohn) I2mo,  i  oo 

*  McKay  and  Larsen's  Principles  and  Practice  of  Butter-making 8vo,  i  50 

Maire's  Modern  Pigments  and  their  Vehicles i2mo,  2  oo 

Mandel's  Handbook  for  Bio-chemical  Laboratory i2mo,  i  50 

*  Martin's  Laboratory  Guide  to  Qualitative  Analysis  with  the  Blowpipe .  .  i2mo,  60 
Mason's  Examination  of  Water.     (Chemical  and  Bacteriological.).  .  ..i2mo,  i  25 

Water-supply.     (Considered  Principally  from   a   Sanitary   Standpoint. 

8vo,  4  oo 

Mathewson's  Chemical  Theory  for  First  Year  College  Students.     (In  Press). 

Matthews's  Textile  Fibres.     2d  Edition,  Rewritten 8vo,  4  oo 

*  Meyer's  Determination  of  Radicle?  in  Carbon  Compounds.     (Tingle). .  i2mo,  i  25 
Miller's  Cyanide  Process I2mo,  i  oo 

Manual  of  Assaying 12010,  i  oo 

Minet's  Production  of  Aluminum  and  its  Industrial  Use.  (Waldo) i2mo,  2  50 

Mixter's  Elementary  Text-book  of  Chemistry I2mo,  i  50 

Morgan's  Elements  of  Physical  Chemistry i2mo,  3  oo 

Outline  of  the  Theory  of  Solutions  and  its  Results i2mo,  i  oo 

*  Physical  Chemistry  for  Electrical  Engineers i2mo,  i  50 

Morse's  Calculations  used  in  Cane-sugar  Factories i6mo,  mor.  i  50 

*  Muir's  History  of  Chemical  Theories  and  Laws 8vo,  4  oo 

Mulliken's  General  Method  for  the  Identification  of  Pure  Organic  Compounds. 

Vol.  I Large  8vo,  5  oo 

O'Driscoll's  Notes  on  the  Treatment  of  Gold  Ores 8vo,  2  oo 

Ostwald's  Conversations  on  Chemistry.     Part  One.    (Ramsey) I2mo,  i  50 

"                  "              "          "            Part  Two.     (Turnbull) i2mo,  2  oo 

*  Palmer's  Practical  Test  Book  of  Chemistry i2mo,  i  oo 

*  Pauli's  Physical  Chemistry  in  the  Service  of  Medicine.     (Fischer) i2mo,  i  25 

*  Penfield's  Notes  on  Determinative  Mineralogy  and  Record  of  Mineral  Tests. 

8vo,  paper,  50 
Tables  of  Minerals,  Including  the   Use   of  Minerals  and  Statistics  of 

Domestic  Production 8vo,  i  oo 

Pictet's  Alkaloids  and  their  Chemical  Constitution.     (Biddle).  -  - 8vo,  5  oo 

Poole's  Calorific  Power  of  Fuels 8vo,  3  oo 

Prescott  and  Winslow's  Elements  of  Water  Bacteriology,  with  Special  Refer- 
ence to  Sanitary  Water  Analysis i2mo,  i  50 

*  Reisig's  Guide  to  Piece-dyeing.  .    8vo,  25  oo 

Richards  and  Woodman's  Air,  Water,  and  Food  from  a  Sanitary  Standpoint.. 8vo,  2  oo 

Ricketts  and  Miller's  Notes  on  Assaying 8vo,  3  oo 

Rideal's  Disinfection  and  the  Preservation  of  Food 8vo,  4  oo 

Sewage  and  the  Bacterial  Purification  of  Sewage 8vo,  4  oo 

5 


Riggs's  Elementary  Manual  for  the  Chemical  Laboratory 8vo,  i  25 

Robine  and  Lenglen's  Cyanide  Industry.     (Le  Clerc) 8vo,  4  oo 

Ruddiman's  Incompatibilities  in  Prescriptions 8vo,  2  oo 

Whys  in  Pharmacy ,  i2mo,  i  oo 

Ruer's  Elements  of  Metallography.     (Mathewson)     (In  Preparation.) 

Sabin's  Industrial  and  Artistic  Technology  of  Paints  and  Varnish 8vo,  3  oo 

Salkowski's  Physiological  and  Pathological  Chemistry.     (Orndorff) Svo,  2  50 

Schimpf's  Essentials  of  Volumetric  Analysis I2mo,  i  25 

*  Qualitative  Chemical  Analysis 8vo,  i  25 

Text-book  of  Volumetric  Analysis i2mo,  2  50 

Smith's  Lecture  Notes  on  Chemistry  for  Dental  Students 8vo,  2  50 

Spencer's  Handbook  for  Cane  Sugar  Manufacturers. i6mo,  mor.  3  oo 

Handbook  for  Chemists  of  Beet-sugar  Houses i6mo,  mor.  3  oo 

Stockbridge's  Rocks  and  Soils 8vo,  2  50 

*  Tillman's  Descriptive  General  Chemistry ,8vo,  3  oo 

*  Elementary  Lessons  in  Heat 8vo,  i  50 

Treadwell's  Qualitative  Analysis.     (Hall) 8vo,  3  oo 

Quantitative  Analysis.     (Hall) 8vo,  4  oo 

Turneaure  and  Russell's  Public  Water-supplies 8vo,  5  oo 

Van  Deventer's  Physical  Chemistry  for  Beginners.     (Boltwood) i2mo,  i  50 

Venable's  Methods  and  Devices  for  Bacterial  Treatment  of  Sewage Svo,  3  oo 

Ward  and  Whipple's  Freshwater  Biology.     (In  Press.) 

Ware's  Beet-sugar  Manufacture  and  Refining.     Vol.  I Small  Svo,  4  oo 

Vol.11 Small8vo,  500 

Washington's  Manual  of  the  Chemical  Analysis  of  Rocks Svo,  2  oo 

*  Weaver's  Military  Explosives Svo,  3  oo 

Wells's  Laboratory  Guide  in  Qualitative  Chemical  Analysis Svo,  i  50 

Short  Course  in  Inorganic  Qualitative  Chemical  Analysis  for  Engineering 

Students i2mo,  i  50 

Text-book  of  Chemical  Arithmetic I2mo,  i  25 

Whipple's  Microscopy  of  Drinking-water Svo,  3  50 

Wilson's  Chlorination  Process I2mo,  i  53 

Cyanide  Processes I2mo,  i  50 

Winton's  Microscopy  of  Vegetable  Foods ,  ,  .  Svo,  7  50 

CIVIL  ENGINEERING. 

BRIDGES  AND  ROOFS.     HYDRAULICS.     MATERIALS   OF    ENGINEER- 
ING.    RAILWAY   ENGINEERING. 

Baker's  Engineers'  Surveying  Instruments i2mo,  3  oo 

Bixby's  Graphical  Computing  Table Paper  19^X24^  inches.  25 

Breed  and  Hosmer's  Principles  and  Practice  of  Surveying.     2  Volumes. 

Vol.  I.     Elementary  Surveying Svo,  3  oo 

Vol.  II.     Higher  Surveying Svo,  2  50 

*  Burr's  Ancient  and  Modern  Engineering  and  the  Isthmian  Canal 8vo,  3  50 

Comstock's  Field  Astronomy  for  Engineers Svo,  2  50 

*  Corthell's  Allowable  Pressures  on  Deep  Foundations i2mo,  i  25 

Crandall's  Text-book  on  Geodesy  and  Least  Squares Svo,  3  oo 

Davis's  Elevation  and  Stadia  Tables Svo,  i  oo 

Elliott's  Engineering  for  Land  Drainage ". i2mo,  i  50 

Practical  Farm  Drainage i2mo,  t  oo 

*Fiebeger's  Treatise  on  Civil  Engineering Svo,  5  oo 

Flemer's  Phototopographic  Methods  and  Instruments Svo,  5  oo 

Folwell's  Sewerage.     (Designing  and  Maintenance.) Svo,  3  oo 

Freitag's  Architectural  Engineering Svo,  3  50 

French  and  Ives's  Stereotomy Svo,  2  50 

Goodhue's  Municipal  Improvements. i2mo,  i  50 

Gore's  Elements  of  Geodesy 8vo,  2  50 

*  Hauch's  and  Rice's  Tables  of  Quantities  for  Preliminary  Estimates  . .  T2mo,  i  25 


Hayford's  Text-book  of  Geodetic  Astronomy 8vo,  3  oo 

Bering's  Ready  Reference  Tables.     (Conversion  Factors) i6mo,  mor.  2  50 

Howe's  Retaining  Walls  for  Earth I2mo»  i  25 

*  Ives's  Adjustments  of  the  Engineer's  Transit  and  Level i6mo,  Bds.  25 

Ives  and  Hilts's  Problems  in  Surveying i6mo,  mor.  i  50 

Johnson's  (J.  B.)  Theory  and  Practice  of  Surveying Small  8vo,  4  oo 

Johnson's  (L.  J.)  Statics  by  Algebraic  and  Graphic  Methods 8vo,  2  oo 

Kinnicutt,  Winslow  and  Pratt's  Purification  of  Sewage.     (In  Preparation.) 
Laplace's    Philosophical   Essay    on    Probabilities.       (Truscott    and   Emory) 

I2mo,  2  oo 

Mahan's  Descriptive  Geometry 8vo,  i  50 

Treatise  on  Civil  Engineering.  (1873-)  (Wood) 8vo,  5  oo 

Merriman's  Elements  of  Precise  Surveying  and  Geodesy v  .  .8vo,  2  50 

Merriman  and  Brooks's  Handbook  for  Surveyors i6mo,  mor.  2  oo 

Nugent's  Plane  Surveying 8vo,  3  50 

Ogden's  Sewer  Construction 8vo,  3  oo 

Sewer  Design i2mo,  2  oo 

Parsons's  Disposal  of  Municipal  Refuse 8vo,  2  oo 

Patton's  Treatise  on  Civil  Engineering 8vo,  half  leather,  7  50 

Reed's  Topographical  Drawing  and  Sketching  .- 4  to,  5  oo 

Rideal's  Sewage  and  the  Bacterial  Purification  of  Sewage 8vo,  4  oo 

Riemer's  Shaft-sinking  under  Difficult  Conditions.  (Corning  and  Peele). .  .8vo,  3  oo 

Siebert  and  Biggin's  Modern  Stone-cutting  and  Masonry 8vo,  i  50 

Smith's  Manual  of  Topographical  Drawing.  (McMillan) 8vo,  2  50 

Soper's  Air  and  Ventilation  of  Subways Large  i2mo,  2  50 

Tracy's  Plane  Surveying i6mo,  mor.  3  oo 

*  Trautwine's  Civil  Engineer's  Pocket-book i6mo,  mor.  5  oo 

Venable's  Garbage  Crematories  in  America 8vo,  2  oo 

Methods  and  Devices  for  Bacterial  Treatment  of  Sewage 8vo,  3  oo 

Wait's  Engineering  and  Architectural  Jurisprudence 8vo,  6  oo 

Sheep,  6  50 

Law  of  Contracts 8vo,  3  oo 

Law  of  Operations  Preliminary  to  Construction  in  Engineering  and  Archi- 
tecture  8vo,  5  oo 

Sheep,  5  50 

Warren's  Stereotomy — Problems  in  Stone-cutting 8vo,  2  50 

*  Waterbury's  Vest-Pocket  Hand-book   of   Mathematics   for   Engineers. 

2^X5!  inches,  mor.  i  oo 
Webb's  Problems  in  the  Use  and  Adjustment  of  Engineering  Instruments. 

i6mo,  mor.  i  25 

Wilson's  (H.  N.)  Topographic  Surveying 8vo,  3  50 

Wilson's  (W.  L.)  Elements  of  Railroad  Track  and  Construction i2mo,  2  oo 

BRIDGES  AND  ROOFS. 

Boiler's  Practical  Treatise  on  the  Construction  of  Iron  Highway  Bridges     8vo,  2  oo 

Burr  and  Falk's  Design  and  Construction  of  Metallic  Bridges 8vc.  5  oo 

Influence  Lines  for  Bridge  and  Roof  Computations 8vo,  3  oo 

Du  Bois's  Mechanics  of  Engineering.     Vol.  II Sntall  4to,  10  oo 

Foster's  Treatise  on  Wooden  Trestle  Bridges 4to,  5  oo 

Fowler's  Ordinary  Foundations 8vo,  3  50 

French  and  Ives's  Stereotomy 8vo,  2  50 

Greene's  Arches  in  Wood,  Iron,  and  Stone .8vo,  2  50 

Bridge  Trusses 8vo, 

Roof  Trusses 8vo, 

Grimm's  Secondary  Stresses  in  Bridge  Trusses 8vo, 

Heller's  Stresses  in  Structures  and  the  Accompanying  Deformations 8vo, 

Howe's  Design  of  Simple  Roof-trusses  in  Wood  and  Steel. 8vo. 

Symmetrical  Masonry  Arches 8vo, 

Treatise  on  Arches 8vo,  4  oc 

7 


Johnson,  Bryan,  and  Turneaure's  Theory  and  Practice  in  the  Designing  of 

Modern  Framed  Structures Small  4to,  10  oo 

Merriman  and  Jacoby's  Text-book  on  Roofs  and  Bridges: 

Part  I.      Stresses  in  Simple  Trusses 8vo,  2  50 

Part  II.    Graphic  Statics 8vo,  2  50 

Part  III.  Bridge  Design 8vo,  2  50 

Part  IV.  Higher  Structures 8vo,  2  50 

Morison's  Memphis  Bridge Oblong  4to,  10  oo 

Sondericker's  Graphic  Statics,  with  Applications  to  Trusses,  Beams,  and  Arches. 

8vo,  2  oo 

Waddell's  De  Pontibus,  Pocket-book  for  Bridge  Engineers i6mo,  mor,  2  oo 

*  Specifications  for  Steel  Bridges i2mo,  50 

Waddell  and  Harrington's  Bridge  Engineering.     (In  Preparation.) 

Wright's  Designing  of  Draw-spans.     Two  parts  in  one  volume 8vo,  3  50 

HYDRAULICS. 

Barnes's  Ice  Formation i 8vo,  3  oo 

Bazin's  Experiments  upon  the  Contraction  of  the  Liquid  Vein  Issuing  from 

an  Orifice.     (Trautwine) 8vo,  2  oo 

Bovey's  Treatise  on  Hydraulics 8vo,  5  oo 

Church's  Diagrams  of  Mean  Velocity  of  Water  in  Open  Channels. 

Oblong  4to .  paper,  i  50 

Hydraulic  Motors 8vo,  2  oo 

Mechanics  of  Engineering 8vo,  6  oo 

Coffin's  Graphical  Solution  of  Hydraulic  Problems i6mo,  mor.  2  50 

Flather's  Dynamometers,  and  the  Measurement  of  Power 12 mo,  3  oo 

Folwell's  Water-supply  Engineering 8vo,  4  oo 

Frizell's  Water-power 8vo,  5  oo 

Fuertes's  Water  and  Public  Health I2mo,  i  50 

Water-filtration  Works i2mo,  2  50 

Ganguillet  and  Kutter's  General  Formula  for  the  Uniform  Flow  of  Water  in 

Rivers  and  Other  Channels.     (Hering  and  Trautwine) 8vo,  4  oo 

Hazen's  Clean  Water  and  How  to  Get  It Large  i2mo,  i  50 

Filtration  of  Public  Water-supplies 8vo,  3  oo 

Hazlehurst's  Towers  and  Tanks  for  Water-works 8vo,  2  50 

Herschel's  115  Experiments  on  the  Carrying  Capacity  of  Large,  Riveted,  Metal 

Conduits 8vo,  2  oo 

Hoyt  and  Grover's  River  Discharge 8vo,  2  oo 

Hubbard  and  Kiersted's  Water- works  Management  and  Maintenance 8vo,  4  oo 

*  Lyndon's  Development  and  Electrical  Distribution  of  Water  Power.  . .  .8vo,  3  oo 
Mason's  Water-supply.     (Considered  Principally  from  a  Sanitary  Standpoint.) 

8vo,  4  oo 

Merriman's  Treatise  on  Hydraulics 8vo,  5  oo 

*  Michie's  Elements  of  Analytical  Mechanics 8vo,  4  oo 

*  Molitor's  Hydraulics  of  Rivers,  Weirs  and  Sluices 8vo,  2  oo 

Richards's  Laboratory  Notes  on  Industrial  Water  Analysis.     (In  Press). 
Schuyler's   Reservoirs  for  Irrigation,   Water-power,   and   Domestic   Water- 
supply Large  8vo,  5  oo 

*  Thomas  and  Watt's  Improvement  of  Rivers 4to,  6  oo 

Turneaure  and'Russell's  Public  Water-supplies 8vo,  5  oo 

Wegmann's  Design  and  Construction  of  Dams.     5th  Ed.,  enlarged 4to,  6  oo 

Water-supply  of  the  City  of  New  York  from  1658  to  1895 4to,  10  oo 

Whipple's  Value  of  Pure  Water Large  I2mo,  i  oo 

Williams  and  Hazen's  Hydraulic  Tables 8vo,  i  50 

Wilson's  Irrigation  Engineering Small  8vo,  4  oo 

Wolff's  Windmill  as  a  Prime  Mover Svo.,  300 

Wood's  Elements  of  Analytical  Mechanics Svo,  3  oo 

Turbines. Svo,  2  50 

8 


MATERIALS  OF  ENGINEERING. 


Baker's  Roads  and  Pavements 8vo,  5  oo 

Treatise  on  Masonry  Construction 8vo,  5  oo 

Birkmire's  Architectural  Iron  and  Steel 8vo,  3  50 

Compound  Riveted  Girders  as  Applied  in  Buildings 8vo,  2  oo 

Black's  United  States  Public  Works Oblong  4to.  5  oo 

Bleininger's  Manufacture  of  Hydraulic  Cement.     (In  Preparation.) 

*  Bovey's  Strength  of  Materials  and  Theory  of  Structures 8vo,  7  50 

Burr's  Elasticity  and  Resistance  of  the  Materials  of  Engineering 8vo,  7  50 

Byrne's  Highway  Construction 8vo,  5  oo 

Inspection  of  the  Materials  and  Workmanship  Employed  in  Construction. 

i6mo,  3  oo 

Church's  Mechanics  of  Engineering 8vo,  6  oo 

Du  Bois's  Mechanics  of  Engineering. 

Vol.   I.  Kinematics,  Statics,  Kinetics Small  4to,  7  50 

Vol.  II.  The  Stresses  in  Framed  Structures,  Strength  of  Materials  and 

Theory  of  Flexures Small  4to,  10  oo 

*Eckel's  Cements,  Limes,  and  Plasters 8vo,  6  oo 

Stone  and  Clay  Products  used  in  Engineering.     (In  Preparation.) 

Fowler's  Ordinary  Foundations 8vo,  3  50 

Graves's  Forest  Mensuration 8vo,  4  oo 

Green's  Principles  of  American  Forestry i2mo,  i  50 

*  Greene's  Structural  Mechanics 8vo,  2  50 

Holly  and  Ladd's  Analysis  of  Mixed  Paints,  Color  Pigments  and  Varnishes 

Large  i2mo,  2  50 
Johnson's  (C.  M.)  Chemical  Analysis  of  Special  Steels.     (In  Preparation.) 

Johnson's  (J.  B.)  Materials  of  Construction Large  8vo,  6  PO 

Keep's  Cast  Iron 8vo,  2  50 

Kidder's  Architects  and  Builders'  Pocket-book i6mo,  5  oo 

Lanza's  Applied  Mechanics 8vo,  7  50 

Maire's  Modern  Pigments  and  their  Vehicles i2mo,  2  oo 

Martens's  Handbook  on  Testing  Materials.     (Henning)     2  vols 8vo,  7  50 

Maurer's  Technical  Mechanics 8vo,  4  oo 

Merrill's  Stones  for  Building  and  Decoration 8vo,  5  oo 

Merriman's  Mechanics  of  Materials 8vo,  5  oo 

*  Strength  of  Materials I2mo,  i  oo 

Metcalf's  Steel.     A  Manual  for  Steel-users i2mo,  2  oo 

Morrison's  Highway  Engineering 8vo,  2  50 

Patton's  Practical  Treatise  on  Foundations 8vo,  5  oo 

Rice's  Concrete  Block  Manufacture 8vo,  2  oo 

Richardson's  Modern  Asphalt  Pavements 8vo,  3  oo 

Richey's  Handbook  for  Superintendents  of  Construction i6mo,  mor.  4  oo 

*  Ries's  Clays:  Their  Occurrence,  Properties,  and  Uses 8vo,  5  oo 

Sabin's  Industrial  and  Artistic  Technology  of  Paints  and  Varnish 8vo,  3  oo 

*Schwarz'sLongleafPinein  Virgin  Forest .ismo,  i  25 

Snow's  Principal  Species  of  Wood 8vo,  3  So 

Spalding's  Hydraulic  Cement i2mo,  2  oo 

Text-book  on  Roads  and  Pavements i2mo,  2  oo 

Taylor  and  Thompson's  Treatise  on  Concrete,  Plain  and  Reinforced 8vo,  5  oo 

Thurston's  Materials  of  Engineering.     In  Three  Parts 8vo,  8  oo 

Parti.     Non-metallic  Materials  of  Engineering  and  Metallurgy 8vo,  2  oo 

Part  II.     Iron  and  Steel 8vo,  3  50 

Part  III.     A  Treatise  on  Brasses,  Bronzes,  and  Other  Alloys  and  their 

Constituents 8vo,  2  50 

Tillson's  Street  Pavements  and  Paving  Materials 8vo,  4  oo 

Turneaure  and  Maurer's  Principles  of  Reinforced  Concrete  Construction..  .8 vo,  3  oo 

Waterbury's  Cement  Laboratory  Manual i2mo,  i  oo 

9 


RAILWAY  ENGINEERING. 

Andrews's  Handbook  for  Street  Railway  Engineers 3x5  inches,  mor.  i  25 

Berg's  Buildings  and  Structures  of  American  Railroads 4to,  5  oo 

Brooks's  Handbook  of  Street  Railroad  Location i6mo,  mor.  50 

Butt's  Civil  Engineer's  Field-book i6mo,  mor.  50 

Crandall's  Railway  and  Other  Earthwork  Tables 8vo,  so 

Transition  Curve i6mo,  mor.  50 

*  Crockett's  Methods  for  Earthwork  Computations 8vo,  50 

Dawson's  "Engineering"  and  Electric  Traction  Pocket-book i6mo,  mor.  5  oo 

Dredge's  History  of  the  Pennsylvania  Railroad:   (1879) Paper,  5  oo 

Fisher's  Table  of  Cubic  Yards Cardboard,  25 

Godwin's  Railroad  Engineers'  Field-book  and  Explorers'  Guide.  .  .  i6mo,  mor.  2  50 
Hudson's  Tables  for  Calculating  the  Cubic  Contents  of  Excavations  and  Em- 
bankments  8vo,  i  oo 

Ives   and  Hilts's   Problems   in  Surveying,  Railroad   Surveying  and  Geodesy 

i6mo,  mor.  i  50 

Molitor  and  Beard's  Manual  for  Resident  Engineers i6mo,  i  oo 

Nagle's  Field  Manual  for  Railroad  Engineers i6mo,  mor.  3  oo 

Philbrick's  Field  Manual  for  Engineers i6mo,  mor.  3  oo 

Raymond's  Railroad  Engineering.     3  volumes. 

Vol.      I.  Railroad  Field  Geometry.     (In  Preparation.) 

Vol.    II.  Elements  of  Railroad  Engineering 8vo,  3  50 

Vol  III.  Railroad  Engineer's  Field  Book.     (In  Preparation.) 

Searles's  Field  Engineering i6mo,  mor.  3  oo 

Railroad  Spiral i6mo,  mor.  i  50 

Taylor's  Prismoidal  Formulae  and  Earthwork 8vo,  i  50 

*Trautwine's  Field  Practice  of  Laying   Out  Circular  Curves   for  Railroads. 

i2mo.  mor,  2  50 

*  Method  of  Calculating  the  Cubic  Contents  of  Excavations  and  Embank- 

ments by  the  Aid  of  Diagrams 8vo,  2  oo 

Webb's  Economics  of  Railroad  Construction Large  i2mo,  2  50 

Railroad  Construction i6mo,  mor.  5  oo 

Wellington's  Economic  Theory  of  the  Location  of  Railways Small  8vo,  5  oo 

DRAWING. 

Barr's  Kinematics  of  Machinery 8vo,  2  50 

*  Bartlett's  Mechanical  Drawing 8vo,  3  oo 

*  "                                                   Abridged  Ed 8vo,  i  50 

Coolidge's  Manual  of  Drawing 8vo,  paper,  i  oo 

Coolidge  and  Freeman's  Elements  of  General  Drafting  for  Mechanical  Engi- 
neers  Oblong  4to,  2  50 

Durley's  Kinematics  of  Machines 8vo,  4  oo 

Emch's  Introduction  to  Projective  Geometry  and  its  Applications 8vo,  2  50 

Hill's  Text-book  on  Shades  and  Shadows,  and  Perspective 8vo,  2  oo 

Jamison's  Advanced  Mechanical  Drawing 8vo,  2  oo 

Elements  of  Mechanical  Drawing 8vo,  2  50 

Jones's  Machine  Design: 

Part  I.     Kinematics  of  Machinery 8vo,  i  50 

Part  II.    Form,  Strength,  and  Proportions  of  Parts 8vo,  3  oo 

MacCord's  Elements  of  Descriptive  Geometry 8vo,  3  oc 

Kinematics ;   or,  Practical  Mechanism 8vOj  5  oo 

Mechanical  Drawing 4to,  4  oo 

Velocity  Diagrams 8vo,  i  50 

McLeod's  Descriptive  Geometry Large  i2mo,  i  50 

*  Mahan's  Descriptive  Geometry  and  Stone-cutting 8vo,  i  50 

Industrial  Drawing.     (Thompson.) 8vo,  3  50 

10 


McLeod's  Descriptive  Geometry Large  i2mo,  i  50 

*  Mahan's  Descriptive  Geometry  and  Stone-cutting 8vo,  i  50 

Industrial  Drawing.  (Thompson) .8vo,  3  50 

Moyer's  Descriptive  Geometry  for  Students  of  Engineering 8vo,  2  oo 

Reed's  Topographical  Drawing  and  Sketching 4  to  5  oo 

Reid's  Course  in  Mechanical  Drawing 8vo,  2  oo 

Text-book  of  Mechanical  Drawing  and  Elementary  Machine  Design. 8vo,  3  oo 

Robinson's  Principles  of  Mechanism 8vo,  3  oo 

Schwamb  and  Merrill's  Elements  of  Mechanism 8vo.  3  oo 

Smith's  (R.  S.)  Manual  of  Topographical  Drawing.  (McMillan) 8vo.  2  50 

Smith  (A.  W.)  and  Marx's  Machine  Design 8vo,  3  oo 

*  Titsworth's  Elements  of  Mechanical  Drawing Oblong  8vo,  i  25 

Warren's  Drafting  Instruments  and  Operations i2mo,  i  25 

Elements  of  Descriptive  Geometry,  Shadows,  and  Perspective 8vo,  3  50 

Elements  of  Machine  Construction  and  Drawing 8vo,  7  50 

Elements  of  Plane  and  Solid  Free-hand  Geometrical  Drawing i2mo,  i  oo 

General  Problems  of  Shades  and  Shadows 8vo,  3  oo 

Manual  of  Elementary  Problems  in  the  Linear  Perspective  of  Form  and 

Shadow 1 2mo,  i  oo 

Manual  of  Elementary  Projection  Drawing i2mo,  i  50 

Plane  Problems  in  Elementary  Geometry   i2mo,  i  25 

Problems,  Theorems,  and  Examples  in  Descriptive  Geometry 8vo,  2  50 

Weisbach's    Kinematics    and    Power    of    Transmission.        (Hermann    and 

Klein) 8vo,  5  oo 

Wilson's  (H.  M.)  Topographic  Surveying 8vo,  3  50 

Wilson's  (V.  T.)  Free-hand  Lettering 8vo,  i  oo 

Free-hand  Perspective 8vo,  2  50 

Woolf's  Elementary  Course  in  Descriptive  Geometry.. Large  8vo.  3  oo 

ELECTRICITY  AND  PHYSICS. 

*  Abegg's  Theory  of  Electrolytic  Dissociation,     (von  Ende) i2mo.  i  25 

Andrews's  Hand-Book  for  Street  Railway  Engineering 3X5  inches,  mor.  i  25 

Anthony  and  Brackett's  Text-book  of  Physics.     (Magie) Large  i2mo,  3  oo 

Anthony's  Theory  of  Electrical  Measurements.     (Ball) i2mo,  i  oo 

Benjamin's  History  of  Electricity 8vo,  3  oo 

Voltaic  Cell.  .1 8vo,  3  oo 

Betts's  Lead  Refining  and  Electrolysis 8vo,  4  oo 

Classen's  Quantitative  Chemical  Analysis  by  Electrolysis.     (Boltwood).  ,8vo,  3  oo 

*  Collins's  Manual  of  Wireless  Telegraphy i2mo,  i  50 

Mor.  2  oo 

Crehore  and  Squicr's  Polarizing  Photo-chronograph 8vo,  3  oo 

*  Danneel's  Electrochemistry.     (Merriam) i2mo,  i  25 

Dawson's  "Engineering"  and  Electric  Traction  Pocket-book  ....  i6mo,  mor.  5  oo 
Dolezalek's  Theory  of  the  Lead  Accumulator  (Storage  Battery),     (von  Ende) 

i2mo,  2  50 

Duhem's  Thermodynamics  and  Chemistry.     (Burgess) 8vo,  4  oo 

Flather's  Dynamometers,  and  the  Measurement  of  Power i2mo,  3  oo 

Gilbert's  De  Magnete.     (Mottelay) '. 8vo,  2  50 

*  Hanchett's  Alternating  Currents i2mo,  i  oo 

Bering's  Ready  Reference  Tables  (Conversion  Factors)    i6mo,  mor.  2  50 

*  Hobart  and  Ellis's  High-speed  Dynamo  Electric  Machinery 8vo,  6  oo 

Holman's  Precision  of  Measurements 8vo,  2  oo 

Telescopic   Mirror-scale  Method,  Adjustments,  and   Tests ....  Largo  8vc ,  75 

*  KarapetofP  s  Experimental  Electrical  Engineering 8vo,  6  oo 

Kinzbrunner's  Testing  of  Continuous-current  Machines.     .       8vo,  2  oo 

Landauer's  Spectrum  Analysis.     (Tingle) 8vo,  3  oo 

Le  Chatelier's  High-temperature  Measurements.  (Boudouard— Burgess)..  i2mo,  3  oo 

Lob's  Electrochemistry  of  Organic  Compounds.     (Lorenz).  .. 8vo,  j  oo 

*  London's  Development  and  Electrical  Distribution  of  Water  Power 8vo,  3  oo 

11 


*  Lyons's  Treatise  on  Electromagnetic  Phenomena.  Vols.  I.  and  II.  8vo,  each  6  oo 

*  Michie's  Elements  of  Wave  Motion  Relating  to  Sound  and  Light 8vo,  4  oo 

Morgan's  Outline  of  the  Theory  of  Solution  and  its  Results.  ..........  12 mo,  i  oo 

*  Physical  Chemistry  for  Electrical  Engineers i2mo,  i   50 

Niaudet's  Elementary  Treatise  on  Electric  Batteries.     (Fishback) .  . .  .  .  i2mo,  2  50 

*  Norris's  Introduction  to  the  Study  of  Electrical  Engineering 8vo,  2  50 

*  Parshall  and  Hobart's  Electric  Machine  Design 4to,  half  mor.  12  50 

Reagan's  Locomotives:   Simple,   Compound,   and  Electric.     New  Edition. 

Large  12 mo,  3  50 

*  Rosenberg's  Electrical  Engineering.    (HaldaneGee  —  Kinzbrunner)  .  .  .8vo,  2  oo 

Ryan,  Norris,  and  Hoxie's  Electrical  Machinery.     Vol.  I 8vo,  2  50 

Schapper's  Laboratory  Guide  for  Students  in  Physical  Chemistry 12 mo,  i   oo 

*  Tillman's  Elementary  Lessons  in  Heat 8vo,  i   50 

Tory  and  Pitcher's  Manual  of  Laboratory  Physics Large  i2mo,  2   oo 

Ulke's  Modern  Electrolytic  Copper  Refining 8vo,  3  oo 

LAW. 

Brennan's  Handbook:    A    Compendium    of    Useful    Legal    Information    for 

Business  Men i6mo,  mor.  5  oo 

*  Davis's  Elements  of  Law 8vo,  2   50 

*  Treatise  on  the  Military  Law  of  United  States 8vo,  7  oo 

Sheep,  7  50 

*  Dudley's  Military  Law  and  the  Procedure  of  Courts-martial.  .  .Large  i2mo,  2  50 

Manual  for  Courts-martial i6mo,  mor.  i   50 

Wait's  Engineering  and  Architectural  Jurisprudence , 8vo,  6  oo 

Sheep,  6  50 

Law  of  Contracts 8vo,  3  oo 

Law  of  Operations  Preliminary  to  Construction  in  Engineering  and  Archi- 
tecture   8vo,  5  oo 

Sheep,  5  50 
MATHEMATICS. 


Baker's  Elliptic  Functions 8vo, 

Briggs's  Elements  of  Plane  Analytic  Geometry.     (Bocher) i2mo, 

*  Buchanan's  Plane  and  Spherical  Trigonometry 8vo, 

Byerley's  Harmonic  Functions 8vo, 

Chandler's  Elements  of  the  Infinitesimal  Calculus 12 mo, 

Coffin's  Vector  Analysis.     (In  Press.) 

Compton's  Manual  of  Logarithmic  Computations 12010, 

*  Dickson's  College  Algebra -Large  i2mo, 

*  Introduction  to  the  Theory  of  Algebraic  Equations. .  „ Large  12 mo, 

Emch's  Introduction  to  Projective  Geometry  and  its  Applications 8vo, 

Fiske's  Functions  of  a  Complex  Variable \ 8vo, 

Halsted's1  Elementary  Synthetic  Geometry 8vo, 


50 
oo 

00 
00 
00 

50 
50 

25 

50 
oo 
So 
Elements  of  Geometry 8vo,         75 

*  Rational  Geometry  . i2mo,         50 

Hyde's  Grassmann's  Space  Analysis 8vo,         oo 

*  Johnson's  (J.  B.)  Three-place  Logarithmic  Tables:  Vest-pocket  size,  paper,         15 

100  copies,  5  oo 

Mounted  on  heavy  cardboard,  8  X   10  inches,  25 

10  copies,  2  oo 
Johnson's  (W.  W.)  Abridged  Editions  of  Differential  and  Integral  Calculus 

Large  12 mo,  i  vol.  2  50 

Curve  Tracing  in  Cartesian  Co-ordinates i2mo,  i  oo 

Differential  Equations 8vo,  i  oo 

Elementary  Treatise  on  Differential  Calculus .Large  i2mo,  i  50 

Elementary  Treatise  on  the  Integral  Calculus. Large  12 mo,  i  50 

Theoretical  Mechanics I2mo,  3  oo 

Theory  of  Errors  and  the  Method  of  Least  Squares 12  mo,  i  50 

Treatise  on  Differential  Calculus .Large  12 mo,  3  oo 

12 


Johnson's  Treatise  on  the  Integral  Calculus Large  i2mo,    3  oo 

Treatise  on  Ordinary  and  Partial  Differential  Equations. .  Large  i2mo,    3  50 
Karapetoff's  Engineering  Applications  of  Higher  Mathematics.      (In   Pre- 
paration.) 
Laplace's  Philosophical  Essay  on  Probabilities.     (Truscott  and  Emory)..i2mo,     2  oo 

*  Ludlow  and  Bass's  Elements  of  Trigonometry  and  Logarithmic  and  Other 

Tables 8vo,     3  oo 

Trigonometry  and  Tables  published  separately Each,     2  oo 

*  Ludlow's  Logarithmic  and  Trigonometric  Tables 8vo,     i  oo 

Macfarlane's  Vector  Analysis  and  Quaternions 8vo,     i  oo 

McManon's  Hyperbolic  Functions 8vo,     i  oo 

Manning's  Irrational  lumbers  and  their  Representation  by  Sequences  and 

Series lamo,     i   25 

Mathematical  Monographs.     Edited  by  Mansfield  Merriman  and  Robert 

S.  Woodward Octavo,  each     i  oo 

No.  i.  History  of  Modern  Mathematics,  by  David  Eugene  Smith. 
No.  2.  Synthetic  Projective  Geometry,  by  George  Bruce  Halsted. 
No.  3.  Determinants,  by  Laenas  Gifford  Weld.  No.  4.  Hyper- 
bolic Functions,  by  James  McMahon.  No.  5.  Harmonic  Func- 
tions, by  William  E.  Byerly.  No.  6.  Grassmanri's  Space  Analysis, 
by  Edward  W.  Hyde.  No.  7.  Probability  and  Theory  of  Errors, 
ty  Robert  S.  Woodward.  No.  8.  Vector  Analysis  and  Quaternions, 
by  Alexander  Macfarlane.  No.  9.  Differential  Equations,  by 
William  Woolsey  Johnson.  No.  10.  The  Solution  of  Equations, 
by  Mansfield  Merriman.  No.  n.  Functions  of  a  Complex  Variable, 
by  Thomas  S.  Fiske. 

Maurer's  Technical  Mechanics 8vo,    4  oo 

Merriman's  Method  of  Least  Squares 8vo,    2  oo 

Solution  of  Equations 8vo,    i  oo 

Rice  and  Johnson's  Differential  and  Integral  Calculus.     2  vols.  in  one. 

Large  i2mo,     i  50 

Elementary  Treatise  on  the  Differential  Calculus Large  I2mo,     3  oo 

Smith's  History  of  Modern  Mathematics 8vo,    i  oo 

*  Veblen  and  Lennes's  Introduction  to  the  Real  Infinitesimal  Analysis  of  One 

Variable 8vo,     2  oo 

*  Waterbury's  Vest  Pocket  Hand-Book  of  Mathematics  for  Engine°rs. 

25  Xsf  inches,  mor.     i  oo 

Weld's  Determinations 8vo,     i  oo 

Wood's  Elements  of  Co-ordinate  Geometry 8vo,    2  oo 

Woodward's  Probability  aid  Theory  of  Errors 8vo,    i  oo 

MECHANICAL  ENGINEERING. 
MATERIALS   OF   ENGINEERING,   STEAM-ENGINES  AND  BOILERS. 

Bacon's  "Forge  Practice i2mo,  i  50 

Baldwin's  Steam  Heating  for  Buildings i2mo,  2  50 

Bair's  Kinematics  of  Machinery 8vo,  2  50 

*  Bartlett's  Mechanical  Drawing 8vo,  3  oo 

*  "  "  "        Abridged  Ed 8vo,    1.50 

Benjamin's  Wrinkles  and  Recipes i2mo,    2  oo 

*  Burr's  Ardent  and  Modern  Engineering  and  the  Isthmian  Canal 8vo,    3  50 

Carpenter's  Experimental  Engineering 8vo,    6  oo 

Heating  and  Ventilating  Buildings 8vo,  4  oo 

Clerk's  Gas  and  Oil  Engine Large  i2mo,  4  oo 

Compton's  First  Lessons  in  Metal  Working I2mo,  i  50 

Compton  and  De  Groodt's  Speed  Lathe i2mo,  i  50 

Coolidge's  Manual  of  Drawing 8vo,  paper,  i  oo 

Coolidge  and  Freeman's  Elements  of  General  Drafting  for  Mechanical  En- 
gineers  : Oblong  4to,  2  50 

13 


Cromwell's  Treatise  on  Belts  and  Pulleys I2mo,  I  50 

Treatise  on  Toothed  Gearing.  . . . .- i2mo,  i  50 

Durley's  Kinematics  of  Machines 8vo,  4  oo 

Flather's  Dynamometers  and  the  Measurement  of  Power, 12 mo,  3  oo 

Rope  Driving I2mo,  2  oo 

Gill's  Gas  and  Fuel  Analysis  for  Engineers I2mo,  i  25 

Goss  s  Locomotive  Sparks 8vo,  2  oo  f 

Greene's  Pumping  Machinery.     (In  Preparation.) 

Bering's  Ready  Reference  Tables  (Conversion  Factors) i6mo,  mor.  2  50 

*  Hobart  and  Ellis's  High  Speed  Dynamo  Electric  Machinery 8vo,  6  oo 

Button's  Gas  Engine 8vo,  5  oo 

Jamison's  Advanced  Mechanical  Drawing 8vo,  2  oo 

Elements  of  Mechanical  Drawing 8vo,  .2  50 

Jones's  Gas  Engine.     (In  Press.) 
Machine  Design: 

Part  I.     Kinematics  of  Machinery 8vo,  i  50 

Part  II.     Form,  Strength,  and  Proportions  of  Parts 8vo,  3  oo 

Kent's  Mechanical  Engineers'  Pocket-book i6mo,  mor.  5  oo 

Kerr's  Power  and  Power  Transmission 8vo,  2  oo 

Leonard's  Machine  Shop  Tools  and  Methods 8vo,  4  oo 

*  Lorenz's  Modern  Refrigerating  Machinery.    (Pope,  Haven,  and  Dean) . .  .  8vo,  4  oo 
MacCord's  Kinematics;   or,  Practical  Mechanism 8vo,  5  oo 

Mechanical  Drawing 4to,  4  oo 

Velocity  Diagrams .8vo,  i  50 

MacFarland's  Standard  Reduction  Factors  for  Gases 8vo,  i  50 

Mahan's  Industrial  Drawing.     (Thompson) - 8vo,  3  50 

Oberg's   Screw  Thread  Systems,   Taps,    Dies,  Cutters,  and   Reamers.      (In 
Press.) 

*  Parshall  and  Hobart's  Electric  Machine  Design Small  4to,  half  leather,  12  50 

Peele's  Compressed  Air  Plant  for  Mines 8vo,  3  oo 

Poole's  Calorific  Power  of  Fuels 8vo,  3  oo 

*  Porter's  Engineering  Reminiscences,  1855  to  1882 8vo,  3  oo 

Reid's  Course  in  Mechanical  Drawing 8vo,  2  oo 

Text-book  of  Mechanical  Drawing  and  Elementary  Machine  Design. 8vo,  3  oo 

Richard's  Compressed  Air i2mo,  i  50 

Robinson's  Principles  of  Mechanism 8vo,  3  oo 

Schwamb  and  Merrill's  Elements  of  Mechanism 8vo,  3  oo 

Smith's  (0.)  Press-working  of  Metals 8vo,  3  oo 

Smith  (A.  W.)  and  Marx's  Machine  Design 8vo,  3  oo 

Sorel '  s  Carbureting  and  Combustion  in  Alcohol  Engines .    (Woodward  and  Preston) . 

Large  i2mo,  3  oo 

Thurston's  Animal  as  a  Machine  and  Prime  Motor,  and  the  Laws  of  Energetics. 

i2mo,  i  oo 

Treatise  on  Friction  and  Lost  Work  in  Machinery  and  Mill  Work...  8vo,  3  oo 

Tillson's  Complete  Automobile  Instructor i6mo,  i  50 

mor.  2  oo 

Titsworth's  Elements  of  Mechanical  Drawing Oblong  8vo,  i   25 

Warren's  Elements  of  Machine  Construction  and  Drawing 8vo,  7  50 

*  Waterbury's  Vest  Pocket  Hand  Book  of  Mathematics  for  Engineers. 

2$X5t  inches,  mor.  i   oo 
Weisbach's    Kinematics    and    the   Power   of   Transmission.     (Herrmann — 

Klein) 8vo,  5  oo 

Machinery  of  Transmission  and  Governors.     (Herrmann — Klein)..  .8vo,  5  oo 

Wood's  Turbines 8vo,  2  50 

MATERIALS   OF  ENGINEERING 

*  Bovey's  Strength  of  Materials  and  Theory  of  Structures .   8vo,  7  50 

Burr's  Elasticity  and  Resistance  of  the  Materials  of  Engineering 8vo,  7  50 

Church's  Mechanics  of  Engineering 8vo,  6  oo 

*  Greene's  Structural  Mechanics 8vo,  2  50 

14     ' 


Holley  and  Ladd's  Analysis  of  Mixed  Paints,  Color  Pigments,  and  Varnishes. 

Large  i2mo,  2  50 

Johnson's  Materials  of  Construction 8vo,  6  oo 

Keep's  Cast  Iron.    8vo,  2  50 

Lanza's  Applied  Mechanics 8vo,  7  50 

Maire's  Modern  Pigments  and  their  Vehicles I2mo,  2  oo 

Martens 's  Handbook  on  Testing  Materials.     (Henning) 8vo,  7  50 

Maurer's  Technical  Mechanics 8vo,  4  oo 

Merriman's  Mechanics  of  Materials 8vo,  5  oo 

*  Strength  of  Materials I2mo,  i  oo 

Metcalf's  Steel.     A  Manual  for  Steel-users 12010,  2  oo 

Sabin's  Industrial  and  Artistic  Technology  of  Paints  and  Varnish 8vo,  3  oo 

Smith's  Materials  of  Machines I2mo,  I  oo 

Thurston's  Materials  of  Engineering 3  vols.,  8vo,  8  oo 

Part  I.       Non-metallic  Materials  of  Engineering  and  Metallurgy. .  .8vo,  2  oo 

Part  II.      Iron  and  Steel 8vo.  3  50 

Part  III.     A  Treatise  on  Brasses,  Bronzes,  and  Other  Alloys  and  their 

Constituents 8vo,  2  50 

Wood's  (De  V.)  Elements  of  Analytical  Mechanics 8vo,  3  oo 

Treatise  on    the    Resistance    of    Materials  and    an  Appendix  on  the 

Preservation  of  Timber 8vo,  2  oo 

Wood's  (M.  P.)  Rustless  Coatings:    Corrosion  and  Electrolysis  of  Iron  and 

Steel 8vo,  4  oo 

STEAM-ENGINES  AND  BOILERS. 

Berry's  Temperature-entropy  Diagram i2mo,  i  25 

Carnot's  Reflections  on  the  Motive  Power  of  Heat.     (Thurston) i2mo,  i  50 

Chase's  Art  of  Pattern  Making i2mo,  2  50 

Creighton's  Steam-engine  and  other  Heat-motors         8vo,  5  oo 

Dawson's  "Engineering"  and  Electric  Traction  Pocket-book i6mo,  mor.  5  oo 

Ford's  Boiler  Making  for  Boiler  Makers i8mo,  i  oo 

*  Gebhardt's  Steam  Power  Plant  Engineering 8vo,  6  oo 

Goss's  Locomotive  Performance 8vo,  5  oo 

Hernenway's  Indicator  Practice  and  Steam-engine  Economy I2mo,  2  oo 

Button's  Heat  and  Heat-engines. 8vo,  5  oo 

Mechanical  Engineering  of  Power  Plants 8vo,  5  oo 

Kent's  Steam  boiler  Economy 8vo,  4  oo 

Kneass's  Practice  and  Theory  of  the  Injector 8vo,  i  50 

MacCord's  Slide-valves 8vo,  2  oo 

Meyer's  Modern  Locomotive  Construction 4to,  10  oo 

Moyer's  Steam  Turbines.     (Tn  Press.) 

Peabody's  Manual  of  the  Steam-engine  Indicator I2mo.  i  50 

Tables  of  the  Properties  of  Saturated  Steam  and  Other  Vapors. 8vo,  i  oo 

Thermodynamics  of  the  Steam-engine  and  Other  Heat-engines 8vo,  5  oo 

Valve-gears  for  Steam-engines 8vo,  2  50 

Peabody  and  Miller's  Steam-boiiers 8vo,  4  oo 

Pray's  Twenty  Years  with  the  Indicator Large  8vo,  2  50 

Pupin's  Thermodynamics  of  Reversible  Cycles  in  Gases  and  Saturated  Vapors. 

(Osterberg) I2mo,  i  25 

Reagan's  Locomotives.    Simple,  Compound,  and  Electric.     New  Edition. 

Large  12 mo,  3  50 

Sinclair's  Locomotive  Engine  Running  and  Management i2mo,  2  oo 

Smart's  Handbook  of  Engineering  Laboratory  Practice I2mo,  2  50 

Snow's  Steam-boiler  Practice. 8vo.  3  oo 

Spangler's  Notes  on  Thermodynamics i2mo,  i  oo 

Valve-gears , 8vo,  2  50 

Spangler,  Greene,  and  Marshall's  Elements  of  Steam-engineering 8vo,  3  oo 

Thomas's  Steam-turbines 8vo,  4  oo 

15 


Egleston's  Catalogue  of  Minerals  and  Synonyms Svo,  2  50 

Goesel's  Minerals  and  Metals:     A  Reference  Book i6mo  mor.  3  oo 

Groth's  Introduction  to  Chemical  Crystallography  (Marshall) i2mo,  i  25 

*  Iddings's  Rock  Minerals    .      8vo,  5  oo 

Johannsen's  Determination  of  Rock-forming  Minerals  in  Thin  Sections 8vo,  4  oo 

*  Martin's  Laboratory  Guide  to  Qualitative  Analysis  with  the  Blowpipe.  121110,  60 
Merrill's  Non-metallic  Minerals:  Their  Occurrence  and  Uses 8vo,  4  oo 

Stones  for  Building  and  Decoration 8vo,  500 

*  Penfield's  Notes  on  Determinative  Mineralogy  and  Record  of  Mineral  Tests. 

Svo,  paper,  50 
Tables    of    Minerals,    Including   the  Use  of  Minerals  and  Statistics  of 

Domestic  Production 8vo,  i  oo 

*  Pirsson's  Rocks  and  Rock  Minerals iimo,  2  50 

*  Richards's  Synopsis  of  Mineral  Characters i2mo,  mor.  i  25 

*  Ries's  Clays:  Their  Occurrence,  Properties,  and  Uses 8vo,  5  oo 

*  Tillman's  Text-book  of  Important  Minerals  and  Rocks 8vo,  2  oo 

MINING. 

*  Beard's  Mine  Gases  and  Explosions Large  i2mo,  3  oo 

Boyd's  Map  of  Southwest  Virginia Pocket-book  lorm,  2  oo 

Resources  of  Southwest  Virginia 8vo,  3  oo 

*  Crane's  Gold  and  Silver    8vo,  5  oo 

Douglas's  Untechnical  Addresses  on  Technical  Subjects i2mo  i  oo 

Eissler's  Modern  High  Explosives 8vo,  4  oo 

Goesel's  Minerals  and  Metals :     A  Reference  Book i6mo,  mor.  3  oo 

Inlseng's  Manual  of  Mining 8vo,  5  oo 

*  Iles's  Lead-smelting I2mo,  2  50 

Miller's  Cyanide  Process I2mo,  i  oo 

O'Driscoll's  Notes  on  the  Treatment  of  Gold  Ores Svo,  2  oo 

Peele's  Compressed  Air  Plant  for  Mines Svo,  3  oo 

Riemer's  Shaft  Sinking  Under  Difficult  Conditions.     (Corning  and  Peele) . .  .8vo,  3  oo 

Robine  and  Lenglen's  Cyanide  Industry.     (Le  Clerc) Svo,  4  oo 

*  Weaver's  Military  Explosives Svo,  3  oo 

Wilson's  Chlorination  Process nmo,  i  so 

Cyanide  Processes I2mo,  I  50 

Hydraulic  and  Placer  Mining.     2d  edition,  rewritten I2mo,  2  50 

Treatise  on  Practical  and  Theoretical  Mine  Ventilation I2mo,  i  25 

SANITARY  SCIENCE. 

Association  of  State  and  National  Food  and  Dairy  Departments,  Hartford  Meeting, 

1906 Svo,  3  oo 

Jamestown  Meeting,  1907 Svo,  3  oo 

*Bashore's  Outlines  of  Practical  Sanitation i2mo,  i  25 

Sanitation  of  a  Country  House i2mo,  i  co 

Sanitation  of  Recreation  Camps  and  Parks i2mo,  i  oo 

Folwell's  Sewerage.     (Designing,  Construction,  and  Maintenance) Svo,  3  oo 

Water-supply  Engineering Svo,  4  oo 

Fowler's  Sewage  Works  Analyses i2mo,  2  oo 

Fuertes's  Water-filtration  Works I2mo,  2  50 

Water  and  Public  Health i2mo,  i  50 

Gerhard's  Guide  to  Sanitary  House-inspection i6mo,  i  oo 

*  Modern  Baths  and  Bath  Houses Svo,  3  oo 

Sanitation  of  Public  Buildings i2mo,  i  50 

Hazen's  Clean  Water  and  How  to  Get  It Large  i2mo,  i  50 

Filtration  of  Public  Water-supplies Svo,  3  oo 

Kinnicut,  Winslow  and  Pratt's  Purification  of  Sewage.     (In  Press.) 

Leach's   Inspection    and    Analysis  of  Food  with  Special  Reference   to  State 

Control 8vo,  7  oo 

18 


50 
50 
oo 
oo 

00 
00 

50 


Mason's  Examination  of  Water.     (Chemical  and  Bacteriological) I2mo,  i  25 

Water-supply.  (  Considered  Principally  from  a  Sanitary  Standpoint) . .  8vo,  4  oo 

*  Merriman's  Elements  of  Sanitary  Engineering 8vo,  2  oo 

Ogden's  Sewer  Design I2mo,  2  oo 

Parsons's  Disposal  of  Municipal  Refuse 8vo,  2  oo 

Prescott  and  Winslow's  Elements  of  Water  Bacteriology,  with  Special  Refer- 
ence to  Sanitary  Water  Analysis I2mo, 

*  Price's  Handbook  on  Sanitation i2mo, 

Richards's  Cost  of  Cleanness.     A  Twentieth  Century  Problem i2mo, 

Cost  of  Food.     A  Study  in  Dietaries i2mo, 

Cost  of  Living  as  Modified  by  Sanitary  Science I2mo, 

Cost  of  Shelter.     A  Study  in  Economics i2mo, 

*  Richards  and  Williams's  Dietary  Computer 8vo, 

Richards  and  Woodman's  Air,   Water,  and  Food  from  a  Sanitary  Stand- 
point  8vo,  oo 

Rideal's   Disinfection  and  the  Preservation  of  Food .   8vo,  oo 

Sewage  and  Bacterial  Purification  of  Sewage 8vo,  4  oo 

Soper's  Air  and  Ventilation  of  Subways Large  i2mo,  2  50 

Turneaure  and  Russell's  Public  Water-supplies 8vo,  5  oo 

Venable's  Garbage  Crematories  in  America 8vo,  2  oo 

Method  and  Devices  for  Bacterial  Treatment  of  Sewage 8vo,  3  oo 

Ward  and  Whipple's  Freshwater  Biology i2mo,  2  50 

Whipple's  Microscopy  of  Drinking-water 8vo,  3  50 

*  Typhod  Fever Large  i2mo,  3  oo 

Value  of  Pure  Water Large  i2mo,  i  oo 

Winslow's  Bacterial  Classification i2mo,  2  50 

Winton's  Microscopy  of  Vegetable  Foods 8vo,  7  50 

MISCELLANEOUS. 

Emmons's  Geological  Guide-book  of  the  Rocky  Mountain  Excursion  of  the 

International  Congress  of  Geologists Large  8vo,  i  50 

Ferrel's  Popular  Treatise  on  the  Winds 8vo,  4  oo 

Fitzgerald's  Boston  Machinist i8mo,  i  oo 

Gannett's  Statistical  Abstract  of  the  World 24010,  75 

Haines's  American  Railway  Management i2mo,  2  50 

*  Hanusek's  The  Microscopy  of  Technical  Products.     (Winton) 8vo,  5  oo 

Owen's  The  Dyeing  and  Cleaning  of  Textile  Fabrics.     (Standage).     (In  Press.) 
Ricketts's  History  of  Rensselaer  Polytechnic  Institute  1824-1894. 

Large  12 mo,  3  oo 

Rotherham's  Emphasized  New  Testament „ Large  8vo,  2  oo 

Standage's  Decoration  of  Wood,  Glass,  Metal,  etc i2mo,  2  oo 

Thome's  Structural  and  Physiological  Botany.    (Bennett) i6mo,  2  25 

Westermaier's  Compendium  of  General  Botany.     (Schneider) 8vo,  2  oo 

Winslow's  Elements  of  Applied  Microscopy I2mo,  i  50 


HEBREW  AND  CHALDEE  TEXT-BOOKS. 

Green's  Elementary  Hebrew  Grammar. I2tno,    i  25 

Gesenius's  Hebrew  and  Chaldee  Lexicon  to  the  Old  Testament  Scriptures. 

(Tregelles) Small  4to,  half  mor.    5  oo 

19 


o 


OVERDUE. 


LD  21-100m-8,'34 


